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<a name="Functions-and-Variables-for-Polynomials"></a>
<div class="header">
<p>
Next: <a href="maxima_81.html#Introduction-to-algebraic-extensions" accesskey="n" rel="next">Introduction to algebraic extensions</a>, Previous: <a href="maxima_79.html#Introduction-to-Polynomials" accesskey="p" rel="previous">Introduction to Polynomials</a>, Up: <a href="maxima_78.html#Polynomials" accesskey="u" rel="up">Polynomials</a> &nbsp; [<a href="maxima_toc.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="maxima_423.html#Function-and-Variable-Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Functions-and-Variables-for-Polynomials-1"></a>
<h3 class="section">14.2 Functions and Variables for Polynomials</h3>

<a name="algebraic"></a><a name="Item_003a-Polynomials_002fdefvr_002falgebraic"></a><dl>
<dt><a name="index-algebraic"></a>Option variable: <strong>algebraic</strong></dt>
<dd><p>Default value: <code>false</code>
</p>
<p><code>algebraic</code> must be set to <code>true</code> in order for the simplification of
algebraic integers to take effect.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Simplification-flags-and-variables">Simplification flags and variables</a>
&middot;</div></dd></dl>

<a name="berlefact"></a><a name="Item_003a-Polynomials_002fdefvr_002fberlefact"></a><dl>
<dt><a name="index-berlefact"></a>Option variable: <strong>berlefact</strong></dt>
<dd><p>Default value: <code>true</code>
</p>
<p>When <code>berlefact</code> is <code>false</code> then the Kronecker factoring
algorithm will be used otherwise the Berlekamp algorithm, which is the
default, will be used.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>


<a name="bezout"></a><a name="Item_003a-Polynomials_002fdeffn_002fbezout"></a><dl>
<dt><a name="index-bezout"></a>Function: <strong>bezout</strong> <em>(<var>p1</var>, <var>p2</var>, <var>x</var>)</em></dt>
<dd>
<p>an alternative to the <code><a href="#resultant">resultant</a></code> command.  It
returns a matrix.  <code>determinant</code> of this matrix is the desired resultant.
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) bezout(a*x+b, c*x^2+d, x);
                         [ b c  - a d ]
(%o1)                    [            ]
                         [  a     b   ]
(%i2) determinant(%);
                            2      2
(%o2)                      a  d + b  c
(%i3) resultant(a*x+b, c*x^2+d, x);
                            2      2
(%o3)                      a  d + b  c
</pre></div>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>


<a name="bothcoef"></a><a name="Item_003a-Polynomials_002fdeffn_002fbothcoef"></a><dl>
<dt><a name="index-bothcoef"></a>Function: <strong>bothcoef</strong> <em>(<var>expr</var>, <var>x</var>)</em></dt>
<dd>
<p>Returns a list whose first member is the coefficient of <var>x</var> in <var>expr</var>
(as found by <code>ratcoef</code> if <var>expr</var> is in CRE form
otherwise by <code>coeff</code>) and whose second member is the remaining part of
<var>expr</var>.  That is, <code>[A, B]</code> where <code><var>expr</var> = A*<var>x</var> + B</code>.
</p>
<p>Example:
</p>
<div class="example">
<pre class="example">(%i1) islinear (expr, x) := block ([c],
        c: bothcoef (rat (expr, x), x),
        is (freeof (x, c) and c[1] # 0))$
(%i2) islinear ((r^2 - (x - r)^2)/x, x);
(%o2)                         true
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="Item_003a-Polynomials_002fdeffn_002fcoeff"></a><dl>
<dt><a name="index-coeff"></a>Function: <strong>coeff</strong> <em><br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>coeff</tt> (<var>expr</var>, <var>x</var>, <var>n</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>coeff</tt> (<var>expr</var>, <var>x</var>)</em></dt>
<dd>
<p>Returns the coefficient of <code><var>x</var>^<var>n</var></code> in <var>expr</var>,
where <var>expr</var> is a polynomial or a monomial term in <var>x</var>.
Other than <code><a href="#ratcoef">ratcoef</a></code> <code>coeff</code> is a strictly syntactical
operation and will only find literal instances of
<code><var>x</var>^<var>n</var></code> in the internal representation of <var>expr</var>.
</p>
<p><code>coeff(<var>expr</var>, <var>x</var>^<var>n</var>)</code> is equivalent
to <code>coeff(<var>expr</var>, <var>x</var>, <var>n</var>)</code>.
<code>coeff(<var>expr</var>, <var>x</var>, 0)</code> returns the remainder of <var>expr</var>
which is free of <var>x</var>.
If omitted, <var>n</var> is assumed to be 1.
</p>
<p><var>x</var> may be a simple variable or a subscripted variable,
or a subexpression of <var>expr</var> which
comprises an operator and all of its arguments.
</p>
<p>It may be possible to compute coefficients of expressions which are equivalent
to <var>expr</var> by applying <code>expand</code> or <code>factor</code>.  <code>coeff</code> itself
does not apply <code>expand</code> or <code>factor</code> or any other function.
</p>
<p><code>coeff</code> distributes over lists, matrices, and equations.
</p>
<p>See also <code><a href="#ratcoef">ratcoef</a></code>.
</p>
<p>Examples:
</p>
<p><code>coeff</code> returns the coefficient <code><var>x</var>^<var>n</var></code> in <var>expr</var>.
</p>
<div class="example">
<pre class="example">(%i1) coeff (b^3*a^3 + b^2*a^2 + b*a + 1, a^3);
                                3
(%o1)                          b
</pre></div>

<p><code>coeff(<var>expr</var>, <var>x</var>^<var>n</var>)</code> is equivalent
to <code>coeff(<var>expr</var>, <var>x</var>, <var>n</var>)</code>.
</p>
<div class="example">
<pre class="example">(%i1) coeff (c[4]*z^4 - c[3]*z^3 - c[2]*z^2 + c[1]*z, z, 3);
(%o1)                         - c
                                 3
</pre><pre class="example">(%i2) coeff (c[4]*z^4 - c[3]*z^3 - c[2]*z^2 + c[1]*z, z^3);
(%o2)                         - c
                                 3
</pre></div>

<p><code>coeff(<var>expr</var>, <var>x</var>, 0)</code> returns the remainder of <var>expr</var>
which is free of <var>x</var>.
</p>
<div class="example">
<pre class="example">(%i1) coeff (a*u + b^2*u^2 + c^3*u^3, b, 0);
                            3  3
(%o1)                      c  u  + a u
</pre></div>

<p><var>x</var> may be a simple variable or a subscripted variable,
or a subexpression of <var>expr</var> which
comprises an operator and all of its arguments.
</p>
<div class="example">
<pre class="example">(%i1) coeff (h^4 - 2*%pi*h^2 + 1, h, 2);
(%o1)                        - 2 %pi
</pre><pre class="example">(%i2) coeff (v[1]^4 - 2*%pi*v[1]^2 + 1, v[1], 2);
(%o2)                        - 2 %pi
</pre><pre class="example">(%i3) coeff (sin(1+x)*sin(x) + sin(1+x)^3*sin(x)^3, sin(1+x)^3);
                                3
(%o3)                        sin (x)
</pre><pre class="example">(%i4) coeff ((d - a)^2*(b + c)^3 + (a + b)^4*(c - d), a + b, 4);
(%o4)                         c - d
</pre></div>

<p><code>coeff</code> itself does not apply <code>expand</code> or <code>factor</code> or any other
function.
</p>
<div class="example">
<pre class="example">(%i1) coeff (c*(a + b)^3, a);
(%o1)                           0
</pre><pre class="example">(%i2) expand (c*(a + b)^3);
                 3          2        2        3
(%o2)           b  c + 3 a b  c + 3 a  b c + a  c
</pre><pre class="example">(%i3) coeff (%, a);
                                2
(%o3)                        3 b  c
</pre><pre class="example">(%i4) coeff (b^3*c + 3*a*b^2*c + 3*a^2*b*c + a^3*c, (a + b)^3);
(%o4)                           0
</pre><pre class="example">(%i5) factor (b^3*c + 3*a*b^2*c + 3*a^2*b*c + a^3*c);
                                  3
(%o5)                      (b + a)  c
</pre><pre class="example">(%i6) coeff (%, (a + b)^3);
(%o6)                           c
</pre></div>

<p><code>coeff</code> distributes over lists, matrices, and equations.
</p>
<div class="example">
<pre class="example">(%i1) coeff ([4*a, -3*a, 2*a], a);
(%o1)                      [4, - 3, 2]
</pre><pre class="example">(%i2) coeff (matrix ([a*x, b*x], [-c*x, -d*x]), x);
                          [  a    b  ]
(%o2)                     [          ]
                          [ - c  - d ]
</pre><pre class="example">(%i3) coeff (a*u - b*v = 7*u + 3*v, u);
(%o3)                         a = 7
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="content"></a><a name="Item_003a-Polynomials_002fdeffn_002fcontent"></a><dl>
<dt><a name="index-content"></a>Function: <strong>content</strong> <em>(<var>p_1</var>, <var>x_1</var>, &hellip;, <var>x_n</var>)</em></dt>
<dd>
<p>Returns a list whose first element is
the greatest common divisor of the coefficients of the terms of the
polynomial <var>p_1</var> in the variable <var>x_n</var> (this is the content) and whose
second element is the polynomial <var>p_1</var> divided by the content.
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) content (2*x*y + 4*x^2*y^2, y);
</pre><pre class="example">                                   2
(%o1)                   [2 x, 2 x y  + y]
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="denom"></a><a name="Item_003a-Polynomials_002fdeffn_002fdenom"></a><dl>
<dt><a name="index-denom"></a>Function: <strong>denom</strong> <em>(<var>expr</var>)</em></dt>
<dd>
<p>Returns the denominator of the rational expression <var>expr</var>.
</p>
<p>See also <code><a href="#num">num</a></code>
</p>
<div class="example">
<pre class="example">(%i1) g1:(x+2)*(x+1)/((x+3)^2);
                         (x + 1) (x + 2)
(%o1)                    ---------------
                                   2
                            (x + 3)
</pre><pre class="example">(%i2) denom(g1);
                                   2
(%o2)                       (x + 3)
</pre><pre class="example">(%i3) g2:sin(x)/10*cos(x)/y;
                          cos(x) sin(x)
(%o3)                     -------------
                              10 y
</pre><pre class="example">(%i4) denom(g2);
(%o4)                         10 y
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Expressions">Expressions</a>
&middot;</div></dd></dl>

<a name="divide"></a><a name="Item_003a-Polynomials_002fdeffn_002fdivide"></a><dl>
<dt><a name="index-divide"></a>Function: <strong>divide</strong> <em>(<var>p_1</var>, <var>p_2</var>, <var>x_1</var>, &hellip;, <var>x_n</var>)</em></dt>
<dd>
<p>computes the quotient and remainder
of the polynomial <var>p_1</var> divided by the polynomial <var>p_2</var>, in a main
polynomial variable, <var>x_n</var>.
The other variables are as in the <code>ratvars</code> function.
The result is a list whose first element is the quotient
and whose second element is the remainder.
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) divide (x + y, x - y, x);
(%o1)                       [1, 2 y]
(%i2) divide (x + y, x - y);
(%o2)                      [- 1, 2 x]
</pre></div>

<p>Note that <code>y</code> is the main variable in the second example.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="eliminate"></a><a name="Item_003a-Polynomials_002fdeffn_002feliminate"></a><dl>
<dt><a name="index-eliminate"></a>Function: <strong>eliminate</strong> <em>([<var>eqn_1</var>, &hellip;, <var>eqn_n</var>], [<var>x_1</var>, &hellip;, <var>x_k</var>])</em></dt>
<dd>
<p>Eliminates variables from equations (or expressions assumed equal to zero) by
taking successive resultants. This returns a list of <code><var>n</var> - <var>k</var></code>
expressions with the <var>k</var> variables <var>x_1</var>, &hellip;, <var>x_k</var> eliminated.
First <var>x_1</var> is eliminated yielding <code><var>n</var> - 1</code> expressions, then
<code>x_2</code> is eliminated, etc.  If <code><var>k</var> = <var>n</var></code> then a single
expression in a list is returned free of the variables <var>x_1</var>, &hellip;,
<var>x_k</var>.  In this case <code>solve</code> is called to solve the last resultant for
the last variable.
</p>
<p>Example:
</p>
<div class="example">
<pre class="example">(%i1) expr1: 2*x^2 + y*x + z;
                                      2
(%o1)                    z + x y + 2 x
(%i2) expr2: 3*x + 5*y - z - 1;
(%o2)                  - z + 5 y + 3 x - 1
(%i3) expr3: z^2 + x - y^2 + 5;
                          2    2
(%o3)                    z  - y  + x + 5
(%i4) eliminate ([expr3, expr2, expr1], [y, z]);
             8         7         6          5          4
(%o4) [7425 x  - 1170 x  + 1299 x  + 12076 x  + 22887 x

                                    3         2
                            - 5154 x  - 1291 x  + 7688 x + 15376]
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;<a href="maxima_424.html#Category_003a-Algebraic-equations">Algebraic equations</a>
&middot;</div></dd></dl>

<a name="ezgcd"></a><a name="Item_003a-Polynomials_002fdeffn_002fezgcd"></a><dl>
<dt><a name="index-ezgcd"></a>Function: <strong>ezgcd</strong> <em>(<var>p_1</var>, <var>p_2</var>, <var>p_3</var>, &hellip;)</em></dt>
<dd>
<p>Returns a list whose first element is the greatest common divisor of the
polynomials <var>p_1</var>, <var>p_2</var>, <var>p_3</var>, &hellip; and whose remaining
elements are the polynomials divided by the greatest common divisor.  This
always uses the <code>ezgcd</code> algorithm.
</p>
<p>See also <code><a href="#gcd">gcd</a></code>, <code><a href="#gcdex">gcdex</a></code>, <code><a href="maxima_360.html#gcdivide">gcdivide</a></code>, and
<code><a href="maxima_290.html#poly_005fgcd">poly_gcd</a></code>.
</p>
<p>Examples:
</p>
<p>The three polynomials have the greatest common divisor <code>2*x-3</code>.  The
gcd is first calculated with the function <code>gcd</code> and then with the function
<code>ezgcd</code>.
</p>
<div class="example">
<pre class="example">(%i1) p1 : 6*x^3-17*x^2+14*x-3;
                        3       2
(%o1)                6 x  - 17 x  + 14 x - 3
(%i2) p2 : 4*x^4-14*x^3+12*x^2+2*x-3;
                    4       3       2
(%o2)            4 x  - 14 x  + 12 x  + 2 x - 3
(%i3) p3 : -8*x^3+14*x^2-x-3;
                          3       2
(%o3)                - 8 x  + 14 x  - x - 3

(%i4) gcd(p1, gcd(p2, p3));
(%o4)                        2 x - 3

(%i5) ezgcd(p1, p2, p3);
                   2               3      2           2
(%o5) [2 x - 3, 3 x  - 4 x + 1, 2 x  - 4 x  + 1, - 4 x  + x + 1]
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="Item_003a-Polynomials_002fdefvr_002ffacexpand"></a><dl>
<dt><a name="index-facexpand"></a>Option variable: <strong>facexpand</strong></dt>
<dd><p>Default value: <code>true</code>
</p>
<p><code>facexpand</code> controls whether the irreducible factors returned by
<code>factor</code> are in expanded (the default) or recursive (normal CRE) form.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="factor"></a><a name="Item_003a-Polynomials_002fdeffn_002ffactor"></a><dl>
<dt><a name="index-factor"></a>Function: <strong>factor</strong> <em><br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>factor</tt> (<var>expr</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>factor</tt> (<var>expr</var>, <var>p</var>)</em></dt>
<dd>
<p>Factors the expression <var>expr</var>, containing any number of variables or 
functions, into factors irreducible over the integers.
<code>factor (<var>expr</var>, <var>p</var>)</code> factors <var>expr</var> over the field of 
rationals with an element adjoined whose minimum polynomial is <var>p</var>.
</p>
<p><code>factor</code> uses <code><a href="maxima_146.html#ifactors">ifactors</a></code> function for factoring integers.
</p>
<p><code><a href="#factorflag">factorflag</a></code> if <code>false</code> suppresses the factoring of integer factors
of rational expressions.
</p>
<p><code><a href="maxima_125.html#dontfactor">dontfactor</a></code> may be set to a list of variables with respect to which
factoring is not to occur.  (It is initially empty).  Factoring also
will not take place with respect to any variables which are less
important (using the variable ordering assumed for CRE form) than
those on the <code>dontfactor</code> list.
</p>
<p><code><a href="#savefactors">savefactors</a></code> if <code>true</code> causes the factors of an expression which
is a product of factors to be saved by certain functions in order to
speed up later factorizations of expressions containing some of the
same factors.
</p>
<p><code><a href="#berlefact">berlefact</a></code> if <code>false</code> then the Kronecker factoring algorithm will
be used otherwise the Berlekamp algorithm, which is the default, will
be used.
</p>
<p><code><a href="#intfaclim">intfaclim</a></code> if <code>true</code> maxima will give up factorization of
integers if no factor is found after trial divisions and Pollard&rsquo;s rho
method.  If set to <code>false</code> (this is the case when the user calls
<code>factor</code> explicitly), complete factorization of the integer will be
attempted.  The user&rsquo;s setting of <code>intfaclim</code> is used for internal
calls to <code>factor</code>.  Thus, <code>intfaclim</code> may be reset to prevent
Maxima from taking an inordinately long time factoring large integers.
</p>
<p><code><a href="#factor_005fmax_005fdegree">factor_max_degree</a></code> if set to a positive integer <code>n</code> will
prevent certain polynomials from being factored if their degree in any
variable exceeds <code>n</code>.
</p>
<p>See also <code><a href="maxima_359.html#collectterms">collectterms</a></code> and <code><a href="#sqfr">sqfr</a></code>
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) factor (2^63 - 1);
                    2
(%o1)              7  73 127 337 92737 649657
(%i2) factor (-8*y - 4*x + z^2*(2*y + x));
(%o2)               (2 y + x) (z - 2) (z + 2)
(%i3) -1 - 2*x - x^2 + y^2 + 2*x*y^2 + x^2*y^2;
                2  2        2    2    2
(%o3)          x  y  + 2 x y  + y  - x  - 2 x - 1
(%i4) block ([dontfactor: [x]], factor (%/36/(1 + 2*y + y^2)));
</pre><pre class="example">                       2
                     (x  + 2 x + 1) (y - 1)
(%o4)                ----------------------
                           36 (y + 1)
</pre><pre class="example">(%i5) factor (1 + %e^(3*x));
                      x         2 x     x
(%o5)              (%e  + 1) (%e    - %e  + 1)
(%i6) factor (1 + x^4, a^2 - 2);
                    2              2
(%o6)             (x  - a x + 1) (x  + a x + 1)
(%i7) factor (-y^2*z^2 - x*z^2 + x^2*y^2 + x^3);
                       2
(%o7)              - (y  + x) (z - x) (z + x)
(%i8) (2 + x)/(3 + x)/(b + x)/(c + x)^2;
                             x + 2
(%o8)               ------------------------
                                           2
                    (x + 3) (x + b) (x + c)
(%i9) ratsimp (%);
</pre><pre class="example">                4                  3
(%o9) (x + 2)/(x  + (2 c + b + 3) x

     2                       2             2                   2
 + (c  + (2 b + 6) c + 3 b) x  + ((b + 3) c  + 6 b c) x + 3 b c )
</pre><pre class="example">(%i10) partfrac (%, x);
           2                   4                3
(%o10) - (c  - 4 c - b + 6)/((c  + (- 2 b - 6) c

     2              2         2                2
 + (b  + 12 b + 9) c  + (- 6 b  - 18 b) c + 9 b ) (x + c))

                 c - 2
 - ---------------------------------
     2                             2
   (c  + (- b - 3) c + 3 b) (x + c)

                         b - 2
 + -------------------------------------------------
             2             2       3      2
   ((b - 3) c  + (6 b - 2 b ) c + b  - 3 b ) (x + b)

                         1
 - ----------------------------------------------
             2
   ((b - 3) c  + (18 - 6 b) c + 9 b - 27) (x + 3)
(%i11) map ('factor, %);
</pre><pre class="example">              2
             c  - 4 c - b + 6                 c - 2
(%o11) - ------------------------- - ------------------------
                2        2                                  2
         (c - 3)  (c - b)  (x + c)   (c - 3) (c - b) (x + c)

                       b - 2                        1
            + ------------------------ - ------------------------
                             2                          2
              (b - 3) (c - b)  (x + b)   (b - 3) (c - 3)  (x + 3)
</pre><pre class="example">(%i12) ratsimp ((x^5 - 1)/(x - 1));
                       4    3    2
(%o12)                x  + x  + x  + x + 1
(%i13) subst (a, x, %);
                       4    3    2
(%o13)                a  + a  + a  + a + 1
(%i14) factor (%th(2), %);
                       2        3        3    2
(%o14)   (x - a) (x - a ) (x - a ) (x + a  + a  + a + 1)
(%i15) factor (1 + x^12);
                       4        8    4
(%o15)               (x  + 1) (x  - x  + 1)
(%i16) factor (1 + x^99);
                 2            6    3
(%o16) (x + 1) (x  - x + 1) (x  - x  + 1)

   10    9    8    7    6    5    4    3    2
 (x   - x  + x  - x  + x  - x  + x  - x  + x  - x + 1)

   20    19    17    16    14    13    11    10    9    7    6
 (x   + x   - x   - x   + x   + x   - x   - x   - x  + x  + x

    4    3            60    57    51    48    42    39    33
 - x  - x  + x + 1) (x   + x   - x   - x   + x   + x   - x

    30    27    21    18    12    9    3
 - x   - x   + x   + x   - x   - x  + x  + 1)
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="factor_005fmax_005fdegree"></a>

<a name="Item_003a-Polynomials_002fdefvr_002ffactor_005fmax_005fdegree"></a><dl>
<dt><a name="index-factor_005fmax_005fdegree"></a>Option variable: <strong>factor_max_degree</strong></dt>
<dd><p>Default value: <code>1000</code>
</p>
<p>When factor_max_degree is set to a positive integer <code>n</code>, it will prevent
Maxima from attempting to factor certain polynomials whose degree in any
variable exceeds <code>n</code>. If <code><a href="#factor_005fmax_005fdegree_005fprint_005fwarning">factor_max_degree_print_warning</a></code> is true,
a warning message will be printed. <code>factor_max_degree</code> can be used to
prevent excessive memory usage and/or computation time and stack overflows.
Note that &quot;obvious&quot; factoring of polynomials such as <code>x^2000+x^2001</code> to
<code>x^2000*(x+1)</code> will still take place. To disable this behavior, set
<code>factor_max_degree</code> to <code>0</code>.
</p>
<p>Example:
</p><div class="example">
<pre class="example">(%i1) factor_max_degree : 100$
</pre><pre class="example">(%i2) factor(x^100-1);
                        2        4    3    2
(%o2) (x - 1) (x + 1) (x  + 1) (x  - x  + x  - x + 1)
   4    3    2            8    6    4    2
 (x  + x  + x  + x + 1) (x  - x  + x  - x  + 1)
   20    15    10    5        20    15    10    5
 (x   - x   + x   - x  + 1) (x   + x   + x   + x  + 1)
   40    30    20    10
 (x   - x   + x   - x   + 1)
</pre><pre class="example">(%i3) factor(x^101-1);
                               101
Refusing to factor polynomial x    - 1
               because its degree exceeds factor_max_degree (100)
                             101
(%o3)                       x    - 1
</pre></div>

<p>See also: <code><a href="#factor_005fmax_005fdegree_005fprint_005fwarning">factor_max_degree_print_warning</a></code>
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="factor_005fmax_005fdegree_005fprint_005fwarning"></a><a name="Item_003a-Polynomials_002fdefvr_002ffactor_005fmax_005fdegree_005fprint_005fwarning"></a><dl>
<dt><a name="index-factor_005fmax_005fdegree_005fprint_005fwarning"></a>Option variable: <strong>factor_max_degree_print_warning</strong></dt>
<dd><p>Default value: <code>true</code>
</p>
<p>When factor_max_degree_print_warning is true, then Maxima will print a
warning message when the factoring of a polynomial is prevented because
its degree exceeds the value of factor_max_degree.
</p>
<p>See also: <code><a href="#factor_005fmax_005fdegree">factor_max_degree</a></code>
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="factorflag"></a><a name="Item_003a-Polynomials_002fdefvr_002ffactorflag"></a><dl>
<dt><a name="index-factorflag"></a>Option variable: <strong>factorflag</strong></dt>
<dd><p>Default value: <code>false</code>
</p>
<p>When <code>factorflag</code> is <code>false</code>, suppresses the factoring of
integer factors of rational expressions.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="factorout"></a><a name="Item_003a-Polynomials_002fdeffn_002ffactorout"></a><dl>
<dt><a name="index-factorout"></a>Function: <strong>factorout</strong> <em>(<var>expr</var>, <var>x_1</var>, <var>x_2</var>, &hellip;)</em></dt>
<dd>
<p>Rearranges the sum <var>expr</var> into a sum of terms of the form 
<code>f (<var>x_1</var>, <var>x_2</var>, &hellip;)*g</code> where <code>g</code> is a product of 
expressions not containing any <var>x_i</var> and <code>f</code> is factored.
</p>
<p>Note that the option variable <code>keepfloat</code> is ignored by <code>factorout</code>.
</p>
<p>Example:
</p>
<div class="example">
<pre class="example">(%i1) expand (a*(x+1)*(x-1)*(u+1)^2);
             2  2          2      2      2
(%o1)     a u  x  + 2 a u x  + a x  - a u  - 2 a u - a
</pre><pre class="example">(%i2) factorout(%,x);
         2
(%o2) a u  (x - 1) (x + 1) + 2 a u (x - 1) (x + 1)
                                              + a (x - 1) (x + 1)
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Expressions">Expressions</a>
&middot;</div></dd></dl>

<a name="factorsum"></a><a name="Item_003a-Polynomials_002fdeffn_002ffactorsum"></a><dl>
<dt><a name="index-factorsum"></a>Function: <strong>factorsum</strong> <em>(<var>expr</var>)</em></dt>
<dd>
<p>Tries to group terms in factors of <var>expr</var> which are sums into groups of
terms such that their sum is factorable.  <code>factorsum</code> can recover the
result of <code>expand ((x + y)^2 + (z + w)^2)</code> but it can&rsquo;t recover
<code>expand ((x + 1)^2 + (x + y)^2)</code> because the terms have variables in
common.
</p>
<p>Example:
</p>
<div class="example">
<pre class="example">(%i1) expand ((x + 1)*((u + v)^2 + a*(w + z)^2));
           2      2                            2      2
(%o1) a x z  + a z  + 2 a w x z + 2 a w z + a w  x + v  x

                                     2        2    2            2
                        + 2 u v x + u  x + a w  + v  + 2 u v + u
(%i2) factorsum (%);
                                   2          2
(%o2)            (x + 1) (a (z + w)  + (v + u) )
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Expressions">Expressions</a>
&middot;</div></dd></dl>

<a name="fasttimes"></a><a name="Item_003a-Polynomials_002fdeffn_002ffasttimes"></a><dl>
<dt><a name="index-fasttimes"></a>Function: <strong>fasttimes</strong> <em>(<var>p_1</var>, <var>p_2</var>)</em></dt>
<dd>
<p>Returns the product of the polynomials <var>p_1</var> and <var>p_2</var> by using a
special algorithm for multiplication of polynomials.  <code>p_1</code> and <code>p_2</code>
should be multivariate, dense, and nearly the same size.  Classical
multiplication is of order <code>n_1 n_2</code> where
<code>n_1</code> is the degree of <code>p_1</code>
and <code>n_2</code> is the degree of <code>p_2</code>.
<code>fasttimes</code> is of order <code>max (n_1, n_2)^1.585</code>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="fullratsimp"></a><a name="Item_003a-Polynomials_002fdeffn_002ffullratsimp"></a><dl>
<dt><a name="index-fullratsimp"></a>Function: <strong>fullratsimp</strong> <em>(<var>expr</var>)</em></dt>
<dd>
<p><code>fullratsimp</code> repeatedly
applies <code>ratsimp</code> followed by non-rational simplification to an
expression until no further change occurs,
and returns the result.
</p>
<p>When non-rational expressions are involved, one call
to <code>ratsimp</code> followed as is usual by non-rational (&quot;general&quot;)
simplification may not be sufficient to return a simplified result.
Sometimes, more than one such call may be necessary.
<code>fullratsimp</code> makes this process convenient.
</p>
<p><code>fullratsimp (<var>expr</var>, <var>x_1</var>, ..., <var>x_n</var>)</code> takes one or more
arguments similar to <code>ratsimp</code> and <code>rat</code>.
</p>
<p>Example:
</p>
<div class="example">
<pre class="example">(%i1) expr: (x^(a/2) + 1)^2*(x^(a/2) - 1)^2/(x^a - 1);
                       a/2     2   a/2     2
                     (x    - 1)  (x    + 1)
(%o1)                -----------------------
                              a
                             x  - 1
(%i2) ratsimp (expr);
                          2 a      a
                         x    - 2 x  + 1
(%o2)                    ---------------
                              a
                             x  - 1
(%i3) fullratsimp (expr);
                              a
(%o3)                        x  - 1
(%i4) rat (expr);
                       a/2 4       a/2 2
                     (x   )  - 2 (x   )  + 1
(%o4)/R/             -----------------------
                              a
                             x  - 1
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Simplification-functions">Simplification functions</a>
&middot;<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="fullratsubst"></a><a name="Item_003a-Polynomials_002fdeffn_002ffullratsubst"></a><dl>
<dt><a name="index-fullratsubst"></a>Function: <strong>fullratsubst</strong> <em>(<var>new</var>, <var>old</var>, <var>expr</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>fullratsubst</tt> (<code><var>old</var> = <var>new</var></code>, <var>expr</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>fullratsubst</tt> (<code>[ <var>old_1</var> = <var>new_1</var>, &hellip;, <var>old_n</var> = <var>new_n</var> ]</code>, <var>expr</var>)</em></dt>
<dd>
<p><code>fullratsubst</code> applies <code><a href="#lratsubst">lratsubst</a></code> repeatedly until <var>expr</var>
stops changing (or <code><a href="#lrats_005fmax_005fiter">lrats_max_iter</a></code> is reached). This function is
useful when the replacement expression and the replaced expression have
one or more variables in common.
</p>
<p><code>fullratsubst</code> accepts its arguments in the format of
<code><a href="#ratsubst">ratsubst</a></code> or <code><a href="#lratsubst">lratsubst</a></code>.
</p>

<p>Examples:
</p>
<ul>
<li> <code>subst</code> can carry out multiple substitutions.
<code>lratsubst</code> is analogous to <code>subst</code>.
</li></ul>
<div class="example">
<pre class="example">(%i2) subst ([a = b, c = d], a + c);
(%o2)                         d + b
(%i3) lratsubst ([a^2 = b, c^2 = d], (a + e)*c*(a + c));
(%o3)                (d + a c) e + a d + b c
</pre></div>
<ul>
<li> If only one substitution is desired, then a single
equation may be given as first argument.
</li></ul>
<div class="example">
<pre class="example">(%i4) lratsubst (a^2 = b, a^3);
(%o4)                          a b
</pre></div>
<ul>
<li> <code>fullratsubst</code> is equivalent to <code>ratsubst</code>
except that it recurses until its result stops changing.
</li></ul>
<div class="example">
<pre class="example">(%i5) ratsubst (b*a, a^2, a^3);
                               2
(%o5)                         a  b
(%i6) fullratsubst (b*a, a^2, a^3);
                                 2
(%o6)                         a b
</pre></div>
<ul>
<li> <code>fullratsubst</code> also accepts a list of equations or a single
equation as first argument.
</li></ul>
<div class="example">
<pre class="example">(%i7) fullratsubst ([a^2 = b, b^2 = c, c^2 = a], a^3*b*c);
(%o7)                           b
(%i8) fullratsubst (a^2 = b*a, a^3);
                                 2
(%o8)                         a b
</pre></div>
<ul>
<li> <code>fullratsubst</code> catches potential infinite recursions. <a href="#lrats_005fmax_005fiter">lrats_max_iter</a>.
</li></ul>
<div class="example">
<pre class="example">(%i9) fullratsubst (b*a^2, a^2, a^3), lrats_max_iter=15;
Warning: fullratsubst1(substexpr,forexpr,expr): reached maximum iterations of 15 . Increase `lrats_max_iter' to increase this limit.
                                     3  15
(%o7)                               a  b
</pre></div>

<p>See also <code><a href="#lrats_005fmax_005fiter">lrats_max_iter</a></code> and <code><a href="#fullratsubstflag">fullratsubstflag</a></code>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>


<a name="fullratsubstflag"></a><a name="Item_003a-Polynomials_002fdefvr_002ffullratsubstflag"></a><dl>
<dt><a name="index-fullratsubstflag"></a>Option variable: <strong>fullratsubstflag</strong></dt>
<dd><p>Default value: <code>false</code>
</p>
<p>An option variable that is set to <code>true</code> in <code><a href="#fullratsubst">fullratsubst</a></code>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>




<a name="gcd"></a><a name="Item_003a-Polynomials_002fdeffn_002fgcd"></a><dl>
<dt><a name="index-gcd"></a>Function: <strong>gcd</strong> <em>(<var>p_1</var>, <var>p_2</var>, <var>x_1</var>, &hellip;)</em></dt>
<dd>
<p>Returns the greatest common divisor of <var>p_1</var> and <var>p_2</var>.  The flag
<code>gcd</code> determines which algorithm is employed.  Setting <code>gcd</code> to
<code>ez</code>, <code>subres</code>, <code>red</code>, or <code>spmod</code> selects the <code>ezgcd</code>,
subresultant <code>prs</code>, reduced, or modular algorithm, respectively.  If
<code>gcd</code> <code>false</code> then <code>gcd (<var>p_1</var>, <var>p_2</var>, <var>x</var>)</code> always
returns 1 for all <var>x</var>.  Many functions (e.g. <code><a href="#ratsimp">ratsimp</a></code>,<!-- /@w -->
<code><a href="#factor">factor</a></code>, etc.) cause gcd&rsquo;s to be taken implicitly.  For homogeneous
polynomials it is recommended that <code>gcd</code> equal to <code>subres</code> be used.
To take the gcd when an algebraic is present, e.g.,
<code>gcd (<var>x</var>^2 - 2*sqrt(2)* <var>x</var> + 2, <var>x</var> - sqrt(2))</code>, the option
variable <code><a href="#algebraic">algebraic</a></code> must be <code>true</code> and <code>gcd</code> must not be
<code>ez</code>.
</p>
<p>The <code>gcd</code> flag, default: <code>spmod</code>, if <code>false</code> will also prevent
the greatest common divisor from being taken when expressions are converted to
canonical rational expression (CRE) form.  This will sometimes speed the
calculation if gcds are not required.
</p>
<p>See also <code><a href="#ezgcd">ezgcd</a></code>, <code><a href="#gcdex">gcdex</a></code>, <code><a href="maxima_360.html#gcdivide">gcdivide</a></code>, and
<code><a href="maxima_290.html#poly_005fgcd">poly_gcd</a></code>.
</p>
<p>Example:
</p>
<div class="example">
<pre class="example">(%i1) p1:6*x^3+19*x^2+19*x+6; 
                        3       2
(%o1)                6 x  + 19 x  + 19 x + 6
(%i2) p2:6*x^5+13*x^4+12*x^3+13*x^2+6*x;
                  5       4       3       2
(%o2)          6 x  + 13 x  + 12 x  + 13 x  + 6 x
(%i3) gcd(p1, p2);
                            2
(%o3)                    6 x  + 13 x + 6
(%i4) p1/gcd(p1, p2), ratsimp;
(%o4)                         x + 1
(%i5) p2/gcd(p1, p2), ratsimp;
                              3
(%o5)                        x  + x
</pre></div>

<p><code><a href="#ezgcd">ezgcd</a></code> returns a list whose first element is the greatest common divisor
of the polynomials <var>p_1</var> and <var>p_2</var>, and whose remaining elements are
the polynomials divided by the greatest common divisor.
</p>
<div class="example">
<pre class="example">(%i6) ezgcd(p1, p2);
                    2                     3
(%o6)           [6 x  + 13 x + 6, x + 1, x  + x]
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>


<a name="gcdex"></a><a name="Item_003a-Polynomials_002fdeffn_002fgcdex"></a><dl>
<dt><a name="index-gcdex"></a>Function: <strong>gcdex</strong> <em><br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>gcdex</tt> (<var>f</var>, <var>g</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>gcdex</tt> (<var>f</var>, <var>g</var>, <var>x</var>)</em></dt>
<dd>
<p>Returns a list <code>[<var>a</var>, <var>b</var>, <var>u</var>]</code> where <var>u</var> is the greatest
common divisor (gcd) of <var>f</var> and <var>g</var>, and <var>u</var> is equal to
<code><var>a</var> <var>f</var> + <var>b</var> <var>g</var></code>.  The arguments <var>f</var> and <var>g</var>
should be univariate polynomials, or else polynomials in <var>x</var> a supplied
main variable since we need to be in a principal ideal domain for this to
work.  The gcd means the gcd regarding <var>f</var> and <var>g</var> as univariate
polynomials with coefficients being rational functions in the other variables.
</p>
<p><code>gcdex</code> implements the Euclidean algorithm, where we have a sequence of
<code>L[i]: [a[i], b[i], r[i]]</code> which are all perpendicular to <code>[f, g, -1]</code>
and the next one is built as if <code>q = quotient(r[i]/r[i+1])</code> then
<code>L[i+2]: L[i] - q L[i+1]</code>, and it terminates at <code>L[i+1]</code> when the
remainder <code>r[i+2]</code> is zero.
</p>
<p>The arguments <var>f</var> and <var>g</var> can be integers.  For this case the function
<code><a href="maxima_146.html#igcdex">igcdex</a></code> is called by <code>gcdex</code>.
</p>
<p>See also <code><a href="#ezgcd">ezgcd</a></code>, <code><a href="#gcd">gcd</a></code>, <code><a href="maxima_360.html#gcdivide">gcdivide</a></code>, and
<code><a href="maxima_290.html#poly_005fgcd">poly_gcd</a></code>.
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) gcdex (x^2 + 1, x^3 + 4);
                       2
                      x  + 4 x - 1  x + 4
(%o1)/R/           [- ------------, -----, 1]
                           17        17
</pre><pre class="example">(%i2) % . [x^2 + 1, x^3 + 4, -1];
(%o2)/R/                        0
</pre></div>

<p>Note that the gcd in the following is <code>1</code> since we work in <code>k(y)[x]</code>,
not the  <code>y+1</code> we would expect in <code>k[y, x]</code>.
</p>
<div class="example">
<pre class="example">(%i1) gcdex (x*(y + 1), y^2 - 1, x);
                               1
(%o1)/R/                 [0, ------, 1]
                              2
                             y  - 1
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>


<a name="gcfactor"></a><a name="Item_003a-Polynomials_002fdeffn_002fgcfactor"></a><dl>
<dt><a name="index-gcfactor"></a>Function: <strong>gcfactor</strong> <em>(<var>n</var>)</em></dt>
<dd>
<p>Factors the Gaussian integer <var>n</var> over the Gaussian integers, i.e., numbers
of the form <code><var>a</var> + <var>b</var> <code>%i</code></code> where <var>a</var> and <var>b</var> are
rational integers (i.e.,  ordinary integers).  Factors are normalized by making
<var>a</var> and <var>b</var> non-negative.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Integers">Integers</a>
&middot;</div></dd></dl>


<a name="gfactor"></a><a name="Item_003a-Polynomials_002fdeffn_002fgfactor"></a><dl>
<dt><a name="index-gfactor"></a>Function: <strong>gfactor</strong> <em>(<var>expr</var>)</em></dt>
<dd>
<p>Factors the polynomial <var>expr</var> over the Gaussian integers
(that is, the integers with the imaginary unit <code>%i</code> adjoined).
This is like <code>factor (<var>expr</var>, <var>a</var>^2+1)</code> where <var>a</var> is <code>%i</code>.
</p>
<p>Example:
</p>
<div class="example">
<pre class="example">(%i1) gfactor (x^4 - 1);
(%o1)           (x - 1) (x + 1) (x - %i) (x + %i)
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>


<a name="gfactorsum"></a><a name="Item_003a-Polynomials_002fdeffn_002fgfactorsum"></a><dl>
<dt><a name="index-gfactorsum"></a>Function: <strong>gfactorsum</strong> <em>(<var>expr</var>)</em></dt>
<dd>
<p>is similar to <code>factorsum</code> but applies <code>gfactor</code> instead
of <code>factor</code>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Expressions">Expressions</a>
&middot;</div></dd></dl>

<a name="hipow"></a><a name="Item_003a-Polynomials_002fdeffn_002fhipow"></a><dl>
<dt><a name="index-hipow"></a>Function: <strong>hipow</strong> <em>(<var>expr</var>, <var>x</var>)</em></dt>
<dd>
<p>Returns the highest explicit exponent of <var>x</var> in <var>expr</var>.
<var>x</var> may be a variable or a general expression.
If <var>x</var> does not appear in <var>expr</var>,
<code>hipow</code> returns <code>0</code>.
</p>
<p><code>hipow</code> does not consider expressions equivalent to <code>expr</code>.  In
particular, <code>hipow</code> does not expand <code>expr</code>, so 
<code>hipow (<var>expr</var>, <var>x</var>)</code> and
<code>hipow (expand (<var>expr</var>, <var>x</var>))</code> may yield different results.
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) hipow (y^3 * x^2 + x * y^4, x);
(%o1)                           2
(%i2) hipow ((x + y)^5, x);
(%o2)                           1
(%i3) hipow (expand ((x + y)^5), x);
(%o3)                           5
(%i4) hipow ((x + y)^5, x + y);
(%o4)                           5
(%i5) hipow (expand ((x + y)^5), x + y);
(%o5)                           0
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Expressions">Expressions</a>
&middot;</div></dd></dl>


<a name="intfaclim"></a><a name="Item_003a-Polynomials_002fdefvr_002fintfaclim"></a><dl>
<dt><a name="index-intfaclim"></a>Option variable: <strong>intfaclim</strong></dt>
<dd><p>Default value: true
</p>
<p>If <code>true</code>, maxima will give up factorization of
integers if no factor is found after trial divisions and Pollard&rsquo;s rho
method and factorization will not be complete.
</p>
<p>When <code>intfaclim</code> is <code>false</code> (this is the case when the user
calls <code>factor</code> explicitly), complete factorization will be
attempted.  <code>intfaclim</code> is set to <code>false</code> when factors are
computed in <code>divisors</code>, <code>divsum</code> and <code>totient</code>.
</p>
<p>Internal calls to <code>factor</code> respect the user-specified value of
<code>intfaclim</code>.  Setting <code>intfaclim</code> to <code>true</code> may reduce
the time spent factoring large integers.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Integers">Integers</a>
&middot;</div></dd></dl>

<a name="keepfloat"></a><a name="Item_003a-Polynomials_002fdefvr_002fkeepfloat"></a><dl>
<dt><a name="index-keepfloat"></a>Option variable: <strong>keepfloat</strong></dt>
<dd><p>Default value: <code>false</code>
</p>
<p>When <code>keepfloat</code> is <code>true</code>, prevents floating
point numbers from being rationalized when expressions which contain
them are converted to canonical rational expression (CRE) form.
</p>
<p>Note that the function <code>solve</code> and those functions calling it 
(<code>eigenvalues</code>, for example) currently ignore this flag, converting 
floating point numbers anyway.
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) rat(x/2.0);

rat: replaced 0.5 by 1/2 = 0.5
                                x
(%o1)/R/                        -
                                2
</pre><pre class="example">(%i2) rat(x/2.0), keepfloat;
(%o2)/R/                      0.5 x
</pre></div>

<p><code>solve</code> ignores <code>keepfloat</code>:
</p>
<div class="example">
<pre class="example">(%i1) solve(1.0-x,x), keepfloat;

rat: replaced 1.0 by 1/1 = 1.0
(%o1)                        [x = 1]
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Numerical-evaluation">Numerical evaluation</a>
&middot;</div></dd></dl>

<a name="lowpow"></a><a name="Item_003a-Polynomials_002fdeffn_002flopow"></a><dl>
<dt><a name="index-lopow"></a>Function: <strong>lopow</strong> <em>(<var>expr</var>, <var>x</var>)</em></dt>
<dd>
<p>Returns the lowest exponent of <var>x</var> which explicitly appears in
<var>expr</var>.  Thus
</p>
<div class="example">
<pre class="example">(%i1) lopow ((x+y)^2 + (x+y)^a, x+y);
(%o1)                       min(a, 2)
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Expressions">Expressions</a>
&middot;</div></dd></dl>


<a name="lratsubst"></a><a name="Item_003a-Polynomials_002fdeffn_002flratsubst"></a><dl>
<dt><a name="index-lratsubst"></a>Function: <strong>lratsubst</strong> <em>(<var>new</var>, <var>old</var>, <var>expr</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>lratsubst</tt> (<code><var>old</var> = <var>new</var></code>, <var>expr</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>lratsubst</tt> (<code>[ <var>old_1</var> = <var>new_1</var>, &hellip;, <var>old_n</var> = <var>new_n</var> ]</code>, <var>expr</var>)</em></dt>
<dd>
<p><code>lratsubst</code> is analogous to <code><a href="maxima_33.html#subst">subst</a></code> except that it uses
<code>ratsubst</code> to perform substitutions.
</p>
<p>The first argument of <code>lratsubst</code> is an equation, a list of
equations or a list of unit length whose first element is a list of
equations (that is, the first argument is identical in format to that
accepted by <code>subst</code>). The substitutions are made in the order given
by the list of equations, that is, from left to right.
</p>
<p>Examples:
</p>

<ul>
<li> <code>subst</code> can carry out multiple substitutions.
<code>lratsubst</code> is analogous to <code>subst</code>.
</li></ul>
<div class="example">
<pre class="example">(%i2) lratsubst ([a = b, c = d], a + c);
(%o2)                         d + b
(%i3) lratsubst ([a^2 = b, c^2 = d], (a + e)*c*(a + c));
(%o3)                (d + a c) e + a d + b c
</pre></div>
<ul>
<li> If only one substitution is desired, then a single
equation may be given as first argument.
</li></ul>
<div class="example">
<pre class="example">(%i4) lratsubst (a^2 = b, a^3);
(%o4)                          a b
</pre></div>
<ul>
<li> A nested list of substitutions can be used&ndash;but it must contain only one list.
</li></ul>
<div class="example">
<pre class="example">(%i5) lratsubst ([[a^2=b*a, b=c]], a^3);

                                      2
(%o5)                               a  c
(%i6) lratsubst ([[a^2=b*a, b=c],[a=b]], a^3);


                                 2
lratsubst: improper argument: [[a  = a b, b = c], [a = b]]
#0: lratsubst(listofeqns=[[a^2 = a*b,b = c],[a = b]],expr=a^3)
 -- an error. To debug this try: debugmode(true);

</pre></div>

<p>See also <code><a href="#fullratsubst">fullratsubst</a></code>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>


<a name="lrats_005fmax_005fiter"></a><a name="Item_003a-Polynomials_002fdefvr_002flrats_005fmax_005fiter"></a><dl>
<dt><a name="index-lrats_005fmax_005fiter"></a>Option variable: <strong>lrats_max_iter</strong></dt>
<dd><p>Default value: <code>100000</code>
</p>
<p>The upper limit on the number of iterations that <code><a href="#fullratsubst">fullratsubst</a></code> and
<code><a href="#lratsubst">lratsubst</a></code> may perform. It must be set to a positive integer. See
the example for <code><a href="#fullratsubst">fullratsubst</a></code>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>


<a name="modulus"></a><a name="Item_003a-Polynomials_002fdefvr_002fmodulus"></a><dl>
<dt><a name="index-modulus"></a>Option variable: <strong>modulus</strong></dt>
<dd><p>Default value: <code>false</code>
</p>
<p>When <code>modulus</code> is a positive number <var>p</var>, operations on canonical rational
expressions (CREs, as returned by <code>rat</code> and related functions) are carried out
modulo <var>p</var>, using the so-called &quot;balanced&quot; modulus system in which <code><var>n</var>
modulo <var>p</var></code> is defined as an integer <var>k</var> in
<code>[-(<var>p</var>-1)/2, ..., 0, ..., (<var>p</var>-1)/2]</code> when <var>p</var> is odd, or
<code>[-(<var>p</var>/2 - 1), ..., 0, ...., <var>p</var>/2]</code> when <var>p</var> is even, such
that <code><var>a</var> <var>p</var> + <var>k</var></code> equals <var>n</var> for some integer <var>a</var>.
</p>
<p>If <var>expr</var> is already in canonical rational expression (CRE) form when
<code>modulus</code> is reset, then you may need to re-rat <var>expr</var>, e.g.,
<code>expr: rat (ratdisrep (expr))</code>, in order to get correct results.
</p>
<p>Typically <code>modulus</code> is set to a prime number.  If <code>modulus</code> is set to
a positive non-prime integer, this setting is accepted, but a warning message is
displayed.  Maxima signals an error, when zero or a negative integer is
assigned to <code>modulus</code>.
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) modulus:7;
(%o1)                           7
(%i2) polymod([0,1,2,3,4,5,6,7]);
(%o2)            [0, 1, 2, 3, - 3, - 2, - 1, 0]
(%i3) modulus:false;
(%o3)                         false
(%i4) poly:x^6+x^2+1;
                            6    2
(%o4)                      x  + x  + 1
(%i5) factor(poly);
                            6    2
(%o5)                      x  + x  + 1
(%i6) modulus:13;
(%o6)                          13
(%i7) factor(poly);
                      2        4      2
(%o7)               (x  + 6) (x  - 6 x  - 2)
(%i8) polymod(%);
                            6    2
(%o8)                      x  + x  + 1
</pre></div>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Integers">Integers</a>
&middot;</div></dd></dl>


<a name="num"></a><a name="Item_003a-Polynomials_002fdeffn_002fnum"></a><dl>
<dt><a name="index-num"></a>Function: <strong>num</strong> <em>(<var>expr</var>)</em></dt>
<dd>
<p>Returns the numerator of <var>expr</var> if it is a ratio.
If <var>expr</var> is not a ratio, <var>expr</var> is returned.
</p>
<p><code>num</code> evaluates its argument.
</p>
<p>See also <code><a href="#denom">denom</a></code>
</p>
<div class="example">
<pre class="example">(%i1) g1:(x+2)*(x+1)/((x+3)^2);
                         (x + 1) (x + 2)
(%o1)                    ---------------
                                   2
                            (x + 3)
</pre><pre class="example">(%i2) num(g1);
(%o2)                    (x + 1) (x + 2)
</pre><pre class="example">(%i3) g2:sin(x)/10*cos(x)/y;
                          cos(x) sin(x)
(%o3)                     -------------
                              10 y
</pre><pre class="example">(%i4) num(g2);
(%o4)                     cos(x) sin(x)
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Expressions">Expressions</a>
&middot;</div></dd></dl>

<a name="polydecomp"></a><a name="Item_003a-Polynomials_002fdeffn_002fpolydecomp"></a><dl>
<dt><a name="index-polydecomp"></a>Function: <strong>polydecomp</strong> <em>(<var>p</var>, <var>x</var>)</em></dt>
<dd>
<p>Decomposes the polynomial <var>p</var> in the variable <var>x</var>
into the functional composition of polynomials in <var>x</var>.
<code>polydecomp</code> returns a list <code>[<var>p_1</var>, ..., <var>p_n</var>]</code> such that
</p>
<div class="example">
<pre class="example">lambda ([x], p_1) (lambda ([x], p_2) (... (lambda ([x], p_n) (x))
  ...))
</pre></div>

<p>is equal to <var>p</var>.
The degree of <var>p_i</var> is greater than 1 for <var>i</var> less than <var>n</var>.
</p>
<p>Such a decomposition is not unique.
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) polydecomp (x^210, x);
                          7   5   3   2
(%o1)                   [x , x , x , x ]
</pre><pre class="example">(%i2) p : expand (subst (x^3 - x - 1, x, x^2 - a));
                6      4      3    2
(%o2)          x  - 2 x  - 2 x  + x  + 2 x - a + 1
</pre><pre class="example">(%i3) polydecomp (p, x);
                        2       3
(%o3)                 [x  - a, x  - x - 1]
</pre></div>

<p>The following function composes <code>L = [e_1, ..., e_n]</code> as functions in
<code>x</code>; it is the inverse of polydecomp:
</p>
<div class="example">
<pre class="example">(%i1) compose (L, x) :=
  block ([r : x], for e in L do r : subst (e, x, r), r) $
</pre></div>

<p>Re-express above example using <code>compose</code>:
</p>
<div class="example">
<pre class="example">(%i1) polydecomp (compose ([x^2 - a, x^3 - x - 1], x), x);
                          2       3
(%o1)          [compose([x  - a, x  - x - 1], x)]
</pre></div>

<p>Note that though <code>compose (polydecomp (<var>p</var>, <var>x</var>), <var>x</var>)</code> always
returns <var>p</var> (unexpanded), <code>polydecomp (compose ([<var>p_1</var>, ...,
<var>p_n</var>], <var>x</var>), <var>x</var>)</code> does <i>not</i> necessarily return
<code>[<var>p_1</var>, ..., <var>p_n</var>]</code>:
</p>
<div class="example">
<pre class="example">(%i1) polydecomp (compose ([x^2 + 2*x + 3, x^2], x), x);
                           2             2
(%o1)           [compose([x  + 2 x + 3, x ], x)]
</pre><pre class="example">(%i2) polydecomp (compose ([x^2 + x + 1, x^2 + x + 1], x), x);
                        2           2
(%o2)        [compose([x  + x + 1, x  + x + 1], x)]
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="polymod"></a><a name="Item_003a-Polynomials_002fdeffn_002fpolymod"></a><dl>
<dt><a name="index-polymod"></a>Function: <strong>polymod</strong> <em><br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>polymod</tt> (<var>p</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>polymod</tt> (<var>p</var>, <var>m</var>)</em></dt>
<dd>
<p>Converts the polynomial <var>p</var> to a modular representation with respect to the
current modulus which is the value of the variable <code>modulus</code>.
</p>
<p><code>polymod (<var>p</var>, <var>m</var>)</code> specifies a modulus <var>m</var> to be used 
instead of the current value of <code>modulus</code>.
</p>
<p>See <code><a href="#modulus">modulus</a></code>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>


<a name="polynomialp"></a><a name="Item_003a-Polynomials_002fdeffn_002fpolynomialp"></a><dl>
<dt><a name="index-polynomialp"></a>Function: <strong>polynomialp</strong> <em><br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>polynomialp</tt> (<var>p</var>, <var>L</var>, <var>coeffp</var>, <var>exponp</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>polynomialp</tt> (<var>p</var>, <var>L</var>, <var>coeffp</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>polynomialp</tt> (<var>p</var>, <var>L</var>)</em></dt>
<dd>
<p>Return <code>true</code> if <var>p</var> is a polynomial in the variables in the list
<var>L</var>.  The predicate <var>coeffp</var> must evaluate to <code>true</code> for each
coefficient, and the predicate <var>exponp</var> must evaluate to <code>true</code> for all
exponents of the variables in <var>L</var>.  If you want to use a non-default value
for <var>exponp</var>, you must supply <var>coeffp</var> with a value even if you want
to use the default for <var>coeffp</var>.
</p>
<p>The command <code>polynomialp (<var>p</var>, <var>L</var>, <var>coeffp</var>)</code> is equivalent to
<code>polynomialp (<var>p</var>, <var>L</var>, <var>coeffp</var>, 'nonnegintegerp)</code> and the
command <code>polynomialp (<var>p</var>, <var>L</var>)</code> is equivalent to
<code>polynomialp (<var>p</var>, L<var>,</var> 'constantp, 'nonnegintegerp)</code>.
</p>
<p>The polynomial needn&rsquo;t be expanded:
</p>
<div class="example">
<pre class="example">(%i1) polynomialp ((x + 1)*(x + 2), [x]);
(%o1)                         true
(%i2) polynomialp ((x + 1)*(x + 2)^a, [x]);
(%o2)                         false
</pre></div>

<p>An example using non-default values for coeffp and exponp:
</p>
<div class="example">
<pre class="example">(%i1) polynomialp ((x + 1)*(x + 2)^(3/2), [x], numberp, numberp);
(%o1)                         true
(%i2) polynomialp ((x^(1/2) + 1)*(x + 2)^(3/2), [x], numberp,
                                                        numberp);
(%o2)                         true
</pre></div>

<p>Polynomials with two variables:
</p>
<div class="example">
<pre class="example">(%i1) polynomialp (x^2 + 5*x*y + y^2, [x]);
(%o1)                         false
(%i2) polynomialp (x^2 + 5*x*y + y^2, [x, y]);
(%o2)                         true
</pre></div>

<p>Polynomial in one variable and accepting any expression free of <code>x</code> as a coefficient.
</p>
<div class="example">
<pre class="example">(%i1) polynomialp (a*x^2 + b*x + c, [x]);
(%o1)                         false
(%i2) polynomialp (a*x^2 + b*x + c, [x], lambda([ex], freeof(x, ex)));
(%o2)                         true
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Predicate-functions">Predicate functions</a>
&middot;<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="quotient"></a><a name="Item_003a-Polynomials_002fdeffn_002fquotient"></a><dl>
<dt><a name="index-quotient"></a>Function: <strong>quotient</strong> <em><br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>quotient</tt> (<var>p_1</var>, <var>p_2</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>quotient</tt> (<var>p_1</var>, <var>p_2</var>, <var>x_1</var>, &hellip;, <var>x_n</var>)</em></dt>
<dd>
<p>Returns the polynomial <var>p_1</var> divided by the polynomial <var>p_2</var>.  The
arguments <var>x_1</var>, &hellip;, <var>x_n</var> are interpreted as in <code>ratvars</code>.
</p>
<p><code>quotient</code> returns the first element of the two-element list returned by
<code><a href="#divide">divide</a></code>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>


<a name="rat"></a><a name="Item_003a-Polynomials_002fdeffn_002frat"></a><dl>
<dt><a name="index-rat"></a>Function: <strong>rat</strong> <em><br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>rat</tt> (<var>expr</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>rat</tt> (<var>expr</var>, <var>x_1</var>, &hellip;, <var>x_n</var>)</em></dt>
<dd>
<p>Converts <var>expr</var> to canonical rational expression (CRE) form by expanding and
combining all terms over a common denominator and cancelling out the
greatest common divisor of the numerator and denominator, as well as
converting floating point numbers to rational numbers within a
tolerance of <code>ratepsilon</code>.
The variables are ordered according
to the <var>x_1</var>, &hellip;, <var>x_n</var>, if specified, as in <code>ratvars</code>.
</p>
<p><code>rat</code> does not generally simplify functions other than addition <code>+</code>,
subtraction <code>-</code>, multiplication <code>*</code>, division <code>/</code>, and
exponentiation to an integer power,
whereas <code>ratsimp</code> does handle those cases.
Note that atoms (numbers and variables) in CRE form are not the
same as they are in the general form.
For example, <code>rat(x)- x</code> yields 
<code>rat(0)</code> which has a different internal representation than 0.
</p>
<p>When <code>ratfac</code> is <code>true</code>, <code>rat</code> yields a partially factored
form for CRE.  During rational operations the expression is
maintained as fully factored as possible without an actual call to the
factor package.  This should always save space and may save some time
in some computations.  The numerator and denominator are still made
relatively prime
(e.g.,  <code>rat((x^2 - 1)^4/(x + 1)^2)</code> yields <code>(x - 1)^4 (x + 1)^2</code>
when <code>ratfac</code> is <code>true</code>),
but the factors within each part may not be relatively prime.
</p>
<p><code>ratprint</code> if <code>false</code> suppresses the printout of the message
informing the user of the conversion of floating point numbers to
rational numbers.
</p>
<p><code>keepfloat</code> if <code>true</code> prevents floating point numbers from being
converted to rational numbers.
</p>
<p>See also <code>ratexpand</code> and  <code>ratsimp</code>.
</p>
<p>Examples:
</p><div class="example">
<pre class="example">(%i1) ((x - 2*y)^4/(x^2 - 4*y^2)^2 + 1)*(y + a)*(2*y + x) /
      (4*y^2 + x^2);
                                           4
                                  (x - 2 y)
              (y + a) (2 y + x) (------------ + 1)
                                   2      2 2
                                 (x  - 4 y )
(%o1)         ------------------------------------
                              2    2
                           4 y  + x
</pre><pre class="example">(%i2) rat (%, y, a, x);
                            2 a + 2 y
(%o2)/R/                    ---------
                             x + 2 y
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="Item_003a-Polynomials_002fdefvr_002fratalgdenom"></a><dl>
<dt><a name="index-ratalgdenom"></a>Option variable: <strong>ratalgdenom</strong></dt>
<dd><p>Default value: <code>true</code>
</p>
<p>When <code>ratalgdenom</code> is <code>true</code>, allows rationalization of denominators
with respect to radicals to take effect.  <code>ratalgdenom</code> has an effect only
when canonical rational expressions (CRE) are used in algebraic mode.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Simplification-flags-and-variables">Simplification flags and variables</a>
&middot;</div></dd></dl>


<a name="ratcoef"></a><a name="Item_003a-Polynomials_002fdeffn_002fratcoef"></a><dl>
<dt><a name="index-ratcoef"></a>Function: <strong>ratcoef</strong> <em><br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>ratcoef</tt> (<var>expr</var>, <var>x</var>, <var>n</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>ratcoef</tt> (<var>expr</var>, <var>x</var>)</em></dt>
<dd>
<p>Returns the coefficient of the expression <code><var>x</var>^<var>n</var></code>
in the expression <var>expr</var>.
If omitted, <var>n</var> is assumed to be 1.
</p>
<p>The return value is free
(except possibly in a non-rational sense) of the variables in <var>x</var>.
If no coefficient of this type exists, 0 is returned.
</p>
<p><code>ratcoef</code>
expands and rationally simplifies its first argument and thus it may
produce answers different from those of <code>coeff</code> which is purely
syntactic.
Thus <code>ratcoef ((x + 1)/y + x, x)</code> returns <code>(y + 1)/y</code> whereas
<code>coeff</code> returns 1.
</p>
<p><code>ratcoef (<var>expr</var>, <var>x</var>, 0)</code>, viewing <var>expr</var> as a sum,
returns a sum of those terms which do not contain <var>x</var>.
Therefore if <var>x</var> occurs to any negative powers, <code>ratcoef</code> should not
be used.
</p>
<p>Since <var>expr</var> is rationally
simplified before it is examined, coefficients may not appear quite
the way they were envisioned.
</p>
<p>Example:
</p>
<div class="example">
<pre class="example">(%i1) s: a*x + b*x + 5$
(%i2) ratcoef (s, a + b);
(%o2)                           x
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="ratdenom"></a><a name="Item_003a-Polynomials_002fdeffn_002fratdenom"></a><dl>
<dt><a name="index-ratdenom"></a>Function: <strong>ratdenom</strong> <em>(<var>expr</var>)</em></dt>
<dd>
<p>Returns the denominator of <var>expr</var>,
after coercing <var>expr</var> to a canonical rational expression (CRE).
The return value is a CRE.
</p>
<p><var>expr</var> is coerced to a CRE by <code>rat</code>
if it is not already a CRE.
This conversion may change the form of <var>expr</var> by putting all terms
over a common denominator.
</p>
<p><code>denom</code> is similar, but returns an ordinary expression instead of a CRE.
Also, <code>denom</code> does not attempt to place all terms over a common
denominator, and thus some expressions which are considered ratios by
<code>ratdenom</code> are not considered ratios by <code>denom</code>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="Item_003a-Polynomials_002fdefvr_002fratdenomdivide"></a><dl>
<dt><a name="index-ratdenomdivide"></a>Option variable: <strong>ratdenomdivide</strong></dt>
<dd><p>Default value: <code>true</code>
</p>
<p>When <code>ratdenomdivide</code> is <code>true</code>,
<code>ratexpand</code> expands a ratio in which the numerator is a sum 
into a sum of ratios,
all having a common denominator.
Otherwise, <code>ratexpand</code> collapses a sum of ratios into a single ratio,
the numerator of which is the sum of the numerators of each ratio.
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) expr: (x^2 + x + 1)/(y^2 + 7);
                            2
                           x  + x + 1
(%o1)                      ----------
                              2
                             y  + 7
(%i2) ratdenomdivide: true$
(%i3) ratexpand (expr);
                       2
                      x        x        1
(%o3)               ------ + ------ + ------
                     2        2        2
                    y  + 7   y  + 7   y  + 7
(%i4) ratdenomdivide: false$
(%i5) ratexpand (expr);
</pre><pre class="example">                            2
                           x  + x + 1
(%o5)                      ----------
                              2
                             y  + 7
</pre><pre class="example">(%i6) expr2: a^2/(b^2 + 3) + b/(b^2 + 3);
                                     2
                           b        a
(%o6)                    ------ + ------
                          2        2
                         b  + 3   b  + 3
(%i7) ratexpand (expr2);
                                  2
                             b + a
(%o7)                        ------
                              2
                             b  + 3
</pre></div>

<div class=categorybox>
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&middot;<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="ratdiff"></a><a name="Item_003a-Polynomials_002fdeffn_002fratdiff"></a><dl>
<dt><a name="index-ratdiff"></a>Function: <strong>ratdiff</strong> <em>(<var>expr</var>, <var>x</var>)</em></dt>
<dd>
<p>Differentiates the rational expression <var>expr</var> with respect to <var>x</var>.
<var>expr</var> must be a ratio of polynomials or a polynomial in <var>x</var>.
The argument <var>x</var> may be a variable or a subexpression of <var>expr</var>.
</p>
<p>The result is equivalent to <code>diff</code>, although perhaps in a different form.
<code>ratdiff</code> may be faster than <code>diff</code>, for rational expressions.
</p>
<p><code>ratdiff</code> returns a canonical rational expression (CRE) if <code>expr</code> is
a CRE.  Otherwise, <code>ratdiff</code> returns a general expression.
</p>
<p><code>ratdiff</code> considers only the dependence of <var>expr</var> on <var>x</var>,
and ignores any dependencies established by <code>depends</code>.
</p>

<p>Example:
</p>
<div class="example">
<pre class="example">(%i1) expr: (4*x^3 + 10*x - 11)/(x^5 + 5);
</pre><pre class="example">                           3
                        4 x  + 10 x - 11
(%o1)                   ----------------
                              5
                             x  + 5
</pre><pre class="example">(%i2) ratdiff (expr, x);
                    7       5       4       2
                 8 x  + 40 x  - 55 x  - 60 x  - 50
(%o2)          - ---------------------------------
                          10       5
                         x   + 10 x  + 25
(%i3) expr: f(x)^3 - f(x)^2 + 7;
                         3       2
(%o3)                   f (x) - f (x) + 7
(%i4) ratdiff (expr, f(x));
                           2
(%o4)                   3 f (x) - 2 f(x)
(%i5) expr: (a + b)^3 + (a + b)^2;
                              3          2
(%o5)                  (b + a)  + (b + a)
(%i6) ratdiff (expr, a + b);
                    2                    2
(%o6)            3 b  + (6 a + 2) b + 3 a  + 2 a
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="ratdisrep"></a><a name="Item_003a-Polynomials_002fdeffn_002fratdisrep"></a><dl>
<dt><a name="index-ratdisrep"></a>Function: <strong>ratdisrep</strong> <em>(<var>expr</var>)</em></dt>
<dd>
<p>Returns its argument as a general expression.
If <var>expr</var> is a general expression, it is returned unchanged.
</p>
<p>Typically <code>ratdisrep</code> is called to convert a canonical rational expression
(CRE) into a general expression.
This is sometimes convenient if one wishes to stop the &quot;contagion&quot;, or
use rational functions in non-rational contexts.
</p>
<p>See also <code><a href="#totaldisrep">totaldisrep</a></code>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="ratexpand"></a><a name="Item_003a-Polynomials_002fdeffn_002fratexpand"></a><dl>
<dt><a name="index-ratexpand"></a>Function: <strong>ratexpand</strong> <em>(<var>expr</var>)</em></dt>
<dt><a name="index-ratexpand-1"></a>Option variable: <strong>ratexpand</strong></dt>
<dd>
<p>Expands <var>expr</var> by multiplying out products of sums and
exponentiated sums, combining fractions over a common denominator,
cancelling the greatest common divisor of the numerator and
denominator, then splitting the numerator (if a sum) into its
respective terms divided by the denominator.
</p>
<p>The return value of <code>ratexpand</code> is a general expression,
even if <var>expr</var> is a canonical rational expression (CRE).
</p>
<p>The switch <code>ratexpand</code> if <code>true</code> will cause CRE
expressions to be fully expanded when they are converted back to
general form or displayed, while if it is <code>false</code> then they will be put
into a recursive form.
See also <code><a href="#ratsimp">ratsimp</a></code>.
</p>
<p>When <code>ratdenomdivide</code> is <code>true</code>,
<code>ratexpand</code> expands a ratio in which the numerator is a sum 
into a sum of ratios,
all having a common denominator.
Otherwise, <code>ratexpand</code> collapses a sum of ratios into a single ratio,
the numerator of which is the sum of the numerators of each ratio.
</p>
<p>When <code>keepfloat</code> is <code>true</code>, prevents floating
point numbers from being rationalized when expressions which contain
them are converted to canonical rational expression (CRE) form.
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) ratexpand ((2*x - 3*y)^3);
                     3         2       2        3
(%o1)          - 27 y  + 54 x y  - 36 x  y + 8 x
(%i2) expr: (x - 1)/(x + 1)^2 + 1/(x - 1);
                         x - 1       1
(%o2)                   -------- + -----
                               2   x - 1
                        (x + 1)
(%i3) expand (expr);
</pre><pre class="example">                    x              1           1
(%o3)          ------------ - ------------ + -----
                2              2             x - 1
               x  + 2 x + 1   x  + 2 x + 1
</pre><pre class="example">(%i4) ratexpand (expr);
                        2
                     2 x                 2
(%o4)           --------------- + ---------------
                 3    2            3    2
                x  + x  - x - 1   x  + x  - x - 1
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="ratfac"></a><a name="Item_003a-Polynomials_002fdefvr_002fratfac"></a><dl>
<dt><a name="index-ratfac"></a>Option variable: <strong>ratfac</strong></dt>
<dd><p>Default value: <code>false</code>
</p>
<p>When <code>ratfac</code> is <code>true</code>, canonical rational expressions (CRE) are
manipulated in a partially factored form.
</p>
<p>During rational operations the expression is maintained as fully factored as
possible without calling <code>factor</code>.
This should always save space and may save time in some computations.
The numerator and denominator are made relatively prime, for example
<code>factor ((x^2 - 1)^4/(x + 1)^2)</code> yields <code>(x - 1)^4 (x + 1)^2</code>,
but the factors within each part may not be relatively prime.
</p>
<p>In the <code>ctensor</code> (Component Tensor Manipulation) package,
Ricci, Einstein, Riemann, and Weyl tensors and the scalar curvature 
are factored automatically when <code>ratfac</code> is <code>true</code>.
<i><code>ratfac</code> should only be
set for cases where the tensorial components are known to consist of
few terms.</i>
</p>
<p>The <code>ratfac</code> and <code>ratweight</code> schemes are incompatible and may not
both be used at the same time.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="ratnumer"></a><a name="Item_003a-Polynomials_002fdeffn_002fratnumer"></a><dl>
<dt><a name="index-ratnumer"></a>Function: <strong>ratnumer</strong> <em>(<var>expr</var>)</em></dt>
<dd>
<p>Returns the numerator of <var>expr</var>,
after coercing <var>expr</var> to a canonical rational expression (CRE).
The return value is a CRE.
</p>
<p><var>expr</var> is coerced to a CRE by <code>rat</code>
if it is not already a CRE.
This conversion may change the form of <var>expr</var> by putting all terms
over a common denominator.
</p>
<p><code>num</code> is similar, but returns an ordinary expression instead of a CRE.
Also, <code>num</code> does not attempt to place all terms over a common denominator,
and thus some expressions which are considered ratios by <code>ratnumer</code>
are not considered ratios by <code>num</code>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="ratp"></a><a name="Item_003a-Polynomials_002fdeffn_002fratp"></a><dl>
<dt><a name="index-ratp"></a>Function: <strong>ratp</strong> <em>(<var>expr</var>)</em></dt>
<dd>
<p>Returns <code>true</code> if <var>expr</var> is a canonical rational expression (CRE) or
extended CRE, otherwise <code>false</code>.
</p>
<p>CRE are created by <code>rat</code> and related functions.
Extended CRE are created by <code>taylor</code> and related functions.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Predicate-functions">Predicate functions</a>
&middot;<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="ratprint"></a><a name="Item_003a-Polynomials_002fdefvr_002fratprint"></a><dl>
<dt><a name="index-ratprint"></a>Option variable: <strong>ratprint</strong></dt>
<dd><p>Default value: <code>true</code>
</p>
<p>When <code>ratprint</code> is <code>true</code>,
a message informing the user of the conversion of floating point numbers
to rational numbers is displayed.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;<a href="maxima_424.html#Category_003a-Numerical-evaluation">Numerical evaluation</a>
&middot;<a href="maxima_424.html#Category_003a-Console-interaction">Console interaction</a>
&middot;</div></dd></dl>

<a name="ratsimp"></a><a name="Item_003a-Polynomials_002fdeffn_002fratsimp"></a><dl>
<dt><a name="index-ratsimp"></a>Function: <strong>ratsimp</strong> <em>(<var>expr</var>)</em></dt>
<dt><a name="index-ratsimp-1"></a>Function: <strong>ratsimp</strong> <em>(<var>expr</var>, <var>x_1</var>, &hellip;, <var>x_n</var>)</em></dt>
<dd>
<p>Simplifies the expression <var>expr</var> and all of its subexpressions, including
the arguments to non-rational functions.  The result is returned as the quotient
of two polynomials in a recursive form, that is, the coefficients of the main
variable are polynomials in the other variables.  Variables may include
non-rational functions (e.g., <code>sin (x^2 + 1)</code>) and the arguments to any
such functions are also rationally simplified.
</p>
<p><code>ratsimp (<var>expr</var>, <var>x_1</var>, ..., <var>x_n</var>)</code>
enables rational simplification with the
specification of variable ordering as in <code>ratvars</code>.
</p>
<p>When <code>ratsimpexpons</code> is <code>true</code>,
<code>ratsimp</code> is applied to the exponents of expressions during simplification.
</p>
<p>See also <code><a href="#ratexpand">ratexpand</a></code>.
Note that <code>ratsimp</code> is affected by some of the
flags which affect <code>ratexpand</code>.
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) sin (x/(x^2 + x)) = exp ((log(x) + 1)^2 - log(x)^2);
</pre><pre class="example">                                         2      2
                   x         (log(x) + 1)  - log (x)
(%o1)        sin(------) = %e
                  2
                 x  + x
</pre><pre class="example">(%i2) ratsimp (%);
                             1          2
(%o2)                  sin(-----) = %e x
                           x + 1
(%i3) ((x - 1)^(3/2) - (x + 1)*sqrt(x - 1))/sqrt((x - 1)*(x + 1));
</pre><pre class="example">                       3/2
                (x - 1)    - sqrt(x - 1) (x + 1)
(%o3)           --------------------------------
                     sqrt((x - 1) (x + 1))
</pre><pre class="example">(%i4) ratsimp (%);
                           2 sqrt(x - 1)
(%o4)                    - -------------
                                 2
                           sqrt(x  - 1)
(%i5) x^(a + 1/a), ratsimpexpons: true;
                               2
                              a  + 1
                              ------
                                a
(%o5)                        x
</pre></div>

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Categories:<a href="maxima_424.html#Category_003a-Simplification-functions">Simplification functions</a>
&middot;<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="Item_003a-Polynomials_002fdefvr_002fratsimpexpons"></a><dl>
<dt><a name="index-ratsimpexpons"></a>Option variable: <strong>ratsimpexpons</strong></dt>
<dd><p>Default value: <code>false</code>
</p>
<p>When <code>ratsimpexpons</code> is <code>true</code>,
<code>ratsimp</code> is applied to the exponents of expressions during simplification.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Simplification-flags-and-variables">Simplification flags and variables</a>
&middot;<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="radsubstflag"></a><a name="Item_003a-Polynomials_002fdefvr_002fradsubstflag"></a><dl>
<dt><a name="index-radsubstflag"></a>Option variable: <strong>radsubstflag</strong></dt>
<dd><p>Default value: <code>false</code>
</p>
<p><code>radsubstflag</code>, if <code>true</code>, permits <code>ratsubst</code> to make
substitutions such as <code>u</code> for <code>sqrt (x)</code> in <code>x</code>.
</p>
<div class=categorybox>
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&middot;</div></dd></dl>

<a name="ratsubst"></a><a name="Item_003a-Polynomials_002fdeffn_002fratsubst"></a><dl>
<dt><a name="index-ratsubst"></a>Function: <strong>ratsubst</strong> <em>(<var>a</var>, <var>b</var>, <var>c</var>)</em></dt>
<dd>
<p>Substitutes <var>a</var> for <var>b</var> in <var>c</var> and returns the resulting expression.
<var>b</var> may be a sum, product, power, etc.
</p>
<p><code>ratsubst</code> knows something of the meaning of expressions
whereas <code>subst</code> does a purely syntactic substitution.
Thus <code>subst (a, x + y, x + y + z)</code> returns <code>x + y + z</code>
whereas <code>ratsubst</code> returns <code>z + a</code>.
</p>
<p>When <code>radsubstflag</code> is <code>true</code>,
<code>ratsubst</code> makes substitutions for radicals in expressions
which don&rsquo;t explicitly contain them.
</p>
<p><code>ratsubst</code> ignores the value <code>true</code> of the option variables
<code>keepfloat</code>, <code>float</code>, and <code>numer</code>.
</p>
<p>Examples:
</p>

<div class="example">
<pre class="example">(%i1) ratsubst (a, x*y^2, x^4*y^3 + x^4*y^8);
                              3      4
(%o1)                      a x  y + a
</pre><pre class="example">(%i2) cos(x)^4 + cos(x)^3 + cos(x)^2 + cos(x) + 1;
               4         3         2
(%o2)       cos (x) + cos (x) + cos (x) + cos(x) + 1
</pre><pre class="example">(%i3) ratsubst (1 - sin(x)^2, cos(x)^2, %);
            4           2                     2
(%o3)    sin (x) - 3 sin (x) + cos(x) (2 - sin (x)) + 3
</pre><pre class="example">(%i4) ratsubst (1 - cos(x)^2, sin(x)^2, sin(x)^4);
                        4           2
(%o4)                cos (x) - 2 cos (x) + 1
</pre><pre class="example">(%i5) radsubstflag: false$
</pre><pre class="example">(%i6) ratsubst (u, sqrt(x), x);
(%o6)                           x
</pre><pre class="example">(%i7) radsubstflag: true$
</pre><pre class="example">(%i8) ratsubst (u, sqrt(x), x);
                                2
(%o8)                          u
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="ratvars"></a><a name="Item_003a-Polynomials_002fdeffn_002fratvars"></a><dl>
<dt><a name="index-ratvars"></a>Function: <strong>ratvars</strong> <em>(<var>x_1</var>, &hellip;, <var>x_n</var>)</em></dt>
<dt><a name="index-ratvars-1"></a>Function: <strong>ratvars</strong> <em>()</em></dt>
<dt><a name="index-ratvars-2"></a>System variable: <strong>ratvars</strong></dt>
<dd>
<p>Declares main variables <var>x_1</var>, &hellip;, <var>x_n</var> for rational expressions.
<var>x_n</var>, if present in a rational expression, is considered the main variable.
Otherwise, <var>x_[n-1]</var> is considered the main variable if present, and so on
through the preceding variables to <var>x_1</var>, which is considered the main
variable only if none of the succeeding variables are present.
</p>
<p>If a variable in a rational expression is not present in the <code>ratvars</code>
list, it is given a lower priority than <var>x_1</var>.
</p>
<p>The arguments to <code>ratvars</code> can be either variables or non-rational
functions such as <code>sin(x)</code>.
</p>
<p>The variable <code>ratvars</code> is a list of the arguments of 
the function <code>ratvars</code> when it was called most recently.
Each call to the function <code>ratvars</code> resets the list.
<code>ratvars ()</code> clears the list.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="Item_003a-Polynomials_002fdefvr_002fratvarswitch"></a><dl>
<dt><a name="index-ratvarswitch"></a>Option variable: <strong>ratvarswitch</strong></dt>
<dd><p>Default value: <code>true</code>
</p>
<p>Maxima keeps an internal list in the Lisp variable <code>VARLIST</code> of the main
variables for rational expressions.  If <code>ratvarswitch</code> is <code>true</code>, 
every evaluation starts with a fresh list <code>VARLIST</code>.  This is the default
behavior.  Otherwise, the main variables from previous evaluations are not 
removed from the internal list <code>VARLIST</code>.
</p>
<p>The main variables, which are declared with the function <code>ratvars</code> are
not affected by the option variable <code>ratvarswitch</code>.
</p>
<p>Examples:
</p>
<p>If <code>ratvarswitch</code> is <code>true</code>, every evaluation starts with a fresh
list <code>VARLIST</code>.
</p>
<div class="example">
<pre class="example">(%i1) ratvarswitch:true$

(%i2) rat(2*x+y^2);
                             2
(%o2)/R/                    y  + 2 x
(%i3) :lisp varlist
($X $Y)

(%i3) rat(2*a+b^2);
                             2
(%o3)/R/                    b  + 2 a

(%i4) :lisp varlist
($A $B)
</pre></div>

<p>If <code>ratvarswitch</code> is <code>false</code>, the main variables from the last 
evaluation are still present.
</p>
<div class="example">
<pre class="example">(%i4) ratvarswitch:false$

(%i5) rat(2*x+y^2);
                             2
(%o5)/R/                    y  + 2 x
(%i6) :lisp varlist
($X $Y)

(%i6) rat(2*a+b^2);
                             2
(%o6)/R/                    b  + 2 a

(%i7) :lisp varlist
($A $B $X $Y)
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;<a href="maxima_424.html#Category_003a-Global-flags">Global flags</a>
&middot;</div></dd></dl>

<a name="Item_003a-Polynomials_002fdeffn_002fratweight"></a><dl>
<dt><a name="index-ratweight"></a>Function: <strong>ratweight</strong> <em><br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>ratweight</tt> (<var>x_1</var>, <var>w_1</var>, &hellip;, <var>x_n</var>, <var>w_n</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>ratweight</tt> ()</em></dt>
<dd>
<p>Assigns a weight <var>w_i</var> to the variable <var>x_i</var>.
This causes a term to be replaced by 0 if its weight exceeds the
value of the variable <code>ratwtlvl</code> (default yields no truncation).
The weight of a term is the sum of the products of the
weight of a variable in the term times its power.
For example, the weight of <code>3 x_1^2 x_2</code> is <code>2 w_1 + w_2</code>.
Truncation according to <code>ratwtlvl</code> is carried out only when multiplying
or exponentiating canonical rational expressions (CRE).
</p>
<p><code>ratweight ()</code> returns the cumulative list of weight assignments.
</p>
<p>Note: The <code>ratfac</code> and <code>ratweight</code> schemes are incompatible and may
not both be used at the same time.
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) ratweight (a, 1, b, 1);
(%o1)                     [a, 1, b, 1]
(%i2) expr1: rat(a + b + 1)$
(%i3) expr1^2;
                  2                  2
(%o3)/R/         b  + (2 a + 2) b + a  + 2 a + 1
(%i4) ratwtlvl: 1$
(%i5) expr1^2;
(%o5)/R/                  2 b + 2 a + 1
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="Item_003a-Polynomials_002fdefvr_002fratweights"></a><dl>
<dt><a name="index-ratweights"></a>System variable: <strong>ratweights</strong></dt>
<dd><p>Default value: <code>[]</code>
</p>
<p><code>ratweights</code> is the list of weights assigned by <code>ratweight</code>.
The list is cumulative:
each call to <code>ratweight</code> places additional items in the list.
</p>
<p><code>kill (ratweights)</code> and <code>save (ratweights)</code> both work as expected.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="Item_003a-Polynomials_002fdefvr_002fratwtlvl"></a><dl>
<dt><a name="index-ratwtlvl"></a>Option variable: <strong>ratwtlvl</strong></dt>
<dd><p>Default value: <code>false</code>
</p>
<p><code>ratwtlvl</code> is used in combination with the <code>ratweight</code>
function to control the truncation of canonical rational expressions (CRE).
For the default value of <code>false</code>, no truncation occurs.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="Item_003a-Polynomials_002fdeffn_002fremainder"></a><dl>
<dt><a name="index-remainder"></a>Function: <strong>remainder</strong> <em><br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>remainder</tt> (<var>p_1</var>, <var>p_2</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>remainder</tt> (<var>p_1</var>, <var>p_2</var>, <var>x_1</var>, &hellip;, <var>x_n</var>)</em></dt>
<dd>
<p>Returns the remainder of the polynomial <var>p_1</var> divided by the polynomial
<var>p_2</var>.  The arguments <var>x_1</var>, &hellip;, <var>x_n</var> are interpreted as in
<code>ratvars</code>.
</p>
<p><code>remainder</code> returns the second element
of the two-element list returned by <code>divide</code>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="resultant"></a><a name="Item_003a-Polynomials_002fdeffn_002fresultant"></a><dl>
<dt><a name="index-resultant"></a>Function: <strong>resultant</strong> <em>(<var>p_1</var>, <var>p_2</var>, <var>x</var>)</em></dt>
<dd>
<p>The function <code>resultant</code> computes the resultant of the two polynomials
<var>p_1</var> and <var>p_2</var>, eliminating the variable <var>x</var>.  The resultant is a
determinant of the coefficients of <var>x</var> in <var>p_1</var> and <var>p_2</var>, which
equals zero if and only if <var>p_1</var> and <var>p_2</var> have a non-constant factor
in common.
</p>
<p>If <var>p_1</var> or <var>p_2</var> can be factored, it may be desirable to call
<code><a href="#factor">factor</a></code> before calling <code>resultant</code>.
</p>
<p>The option variable <code>resultant</code> controls which algorithm will be used to
compute the resultant.  See the option variable
<code><a href="#option_005fresultant">resultant</a></code>.
</p>
<p>The function <code><a href="#bezout">bezout</a></code> takes the same arguments as <code>resultant</code> and
returns a matrix.  The determinant of the return value is the desired resultant.
</p>
<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) resultant(2*x^2+3*x+1, 2*x^2+x+1, x);
(%o1)                           8
(%i2) resultant(x+1, x+1, x);
(%o2)                           0
(%i3) resultant((x+1)*x, (x+1), x);
(%o3)                           0
(%i4) resultant(a*x^2+b*x+1, c*x + 2, x);
                         2
(%o4)                   c  - 2 b c + 4 a

(%i5) bezout(a*x^2+b*x+1, c*x+2, x);
</pre><pre class="example">                        [ 2 a  2 b - c ]
(%o5)                   [              ]
                        [  c      2    ]
</pre><pre class="example">(%i6) determinant(%);
(%o6)                   4 a - (2 b - c) c
</pre></div>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="option_005fresultant"></a><a name="Item_003a-Polynomials_002fdefvr_002fresultant"></a><dl>
<dt><a name="index-resultant-1"></a>Option variable: <strong>resultant</strong></dt>
<dd><p>Default value: <code>subres</code>
</p>
<p>The option variable <code>resultant</code> controls which algorithm will be used to
compute the resultant with the function <code><a href="#resultant">resultant</a></code>.  The possible
values are:
</p>
<dl compact="compact">
<dt><code>subres</code></dt>
<dd><p>for the subresultant polynomial remainder sequence (PRS) algorithm,
</p></dd>
<dt><code>mod</code></dt>
<dd><p>(not enabled) for the modular resultant algorithm, and 
</p></dd>
<dt><code>red</code></dt>
<dd><p>for the reduced polynomial remainder sequence (PRS) algorithm.
</p></dd>
</dl>

<p>On most problems the default value <code>subres</code> should be best.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="savefactors"></a><a name="Item_003a-Polynomials_002fdefvr_002fsavefactors"></a><dl>
<dt><a name="index-savefactors"></a>Option variable: <strong>savefactors</strong></dt>
<dd><p>Default value: <code>false</code>
</p>
<p>When <code>savefactors</code> is <code>true</code>, causes the factors of an
expression which is a product of factors to be saved by certain
functions in order to speed up later factorizations of expressions
containing some of the same factors.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>

<a name="showratvars"></a><a name="Item_003a-Polynomials_002fdeffn_002fshowratvars"></a><dl>
<dt><a name="index-showratvars"></a>Function: <strong>showratvars</strong> <em>(<var>expr</var>)</em></dt>
<dd>
<p>Returns a list of the canonical rational expression (CRE) variables in
expression <code>expr</code>.
</p>
<p>See also <code><a href="#ratvars">ratvars</a></code>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;<a href="maxima_424.html#Category_003a-Display-functions">Display functions</a>
&middot;</div></dd></dl>


<a name="sqfr"></a><a name="Item_003a-Polynomials_002fdeffn_002fsqfr"></a><dl>
<dt><a name="index-sqfr"></a>Function: <strong>sqfr</strong> <em>(<var>expr</var>)</em></dt>
<dd>
<p>is similar to <code><a href="#factor">factor</a></code> except that the polynomial factors are
&quot;square-free.&quot;  That is, they have factors only of degree one.
This algorithm, which is also used by the first stage of <code><a href="#factor">factor</a></code>, utilizes
the fact that a polynomial has in common with its n&rsquo;th derivative all
its factors of degree greater than n.  Thus by taking greatest common divisors
with the polynomial of
the derivatives with respect to each variable in the polynomial, all
factors of degree greater than 1 can be found.
</p>
<p>Example:
</p>
<div class="example">
<pre class="example">(%i1) sqfr (4*x^4 + 4*x^3 - 3*x^2 - 4*x - 1);
                                2   2
(%o1)                  (2 x + 1)  (x  - 1)
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;</div></dd></dl>


<a name="Item_003a-Polynomials_002fdeffn_002ftellrat"></a><dl>
<dt><a name="index-tellrat"></a>Function: <strong>tellrat</strong> <em><br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>tellrat</tt> (<var>p_1</var>, &hellip;, <var>p_n</var>) <br>&nbsp;&nbsp;&nbsp;&nbsp;<tt>tellrat</tt> ()</em></dt>
<dd>
<p>Adds to the ring of algebraic integers known to Maxima
the elements which are the solutions of the polynomials <var>p_1</var>, &hellip;,
<var>p_n</var>.  Each argument <var>p_i</var> is a polynomial with integer coefficients.
</p>
<p><code>tellrat (<var>x</var>)</code> effectively means substitute 0 for <var>x</var> in rational
functions.
</p>
<p><code>tellrat ()</code> returns a list of the current substitutions.
</p>
<p><code>algebraic</code> must be set to <code>true</code> in order for the simplification of
algebraic integers to take effect.
</p>
<p>Maxima initially knows about the imaginary unit <code>%i</code>
and all roots of integers.
</p>
<p>There is a command <code>untellrat</code> which takes kernels and
removes <code>tellrat</code> properties.
</p>
<p>When <code>tellrat</code>&rsquo;ing a multivariate
polynomial, e.g., <code>tellrat (x^2 - y^2)</code>, there would be an ambiguity as to
whether to substitute <code><var>y</var>^2</code> for <code><var>x</var>^2</code>
or vice versa.  
Maxima picks a particular ordering, but if the user wants to specify which, e.g.
<code>tellrat (y^2 = x^2)</code> provides a syntax which says replace
<code><var>y</var>^2</code> by <code><var>x</var>^2</code>.
</p>

<p>Examples:
</p>
<div class="example">
<pre class="example">(%i1) 10*(%i + 1)/(%i + 3^(1/3));
                           10 (%i + 1)
(%o1)                      -----------
                                  1/3
                            %i + 3
(%i2) ev (ratdisrep (rat(%)), algebraic);
             2/3      1/3              2/3      1/3
(%o2)    (4 3    - 2 3    - 4) %i + 2 3    + 4 3    - 2
(%i3) tellrat (1 + a + a^2);
                            2
(%o3)                     [a  + a + 1]
(%i4) 1/(a*sqrt(2) - 1) + a/(sqrt(3) + sqrt(2));
                      1                 a
(%o4)           ------------- + -----------------
                sqrt(2) a - 1   sqrt(3) + sqrt(2)
(%i5) ev (ratdisrep (rat(%)), algebraic);
         (7 sqrt(3) - 10 sqrt(2) + 2) a - 2 sqrt(2) - 1
(%o5)    ----------------------------------------------
                               7
(%i6) tellrat (y^2 = x^2);
                        2    2   2
(%o6)                 [y  - x , a  + a + 1]
</pre></div>

<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="totaldisrep"></a><a name="Item_003a-Polynomials_002fdeffn_002ftotaldisrep"></a><dl>
<dt><a name="index-totaldisrep"></a>Function: <strong>totaldisrep</strong> <em>(<var>expr</var>)</em></dt>
<dd>
<p>Converts every subexpression of <var>expr</var> from canonical rational expressions
(CRE) to general form and returns the result.
If <var>expr</var> is itself in CRE form then <code>totaldisrep</code> is identical to
<code>ratdisrep</code>.
</p>
<p><code>totaldisrep</code> may be useful for
ratdisrepping expressions such as equations, lists, matrices, etc., which
have some subexpressions in CRE form.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<a name="untelltat"></a><a name="Item_003a-Polynomials_002fdeffn_002funtellrat"></a><dl>
<dt><a name="index-untellrat"></a>Function: <strong>untellrat</strong> <em>(<var>x_1</var>, &hellip;, <var>x_n</var>)</em></dt>
<dd>
<p>Removes <code>tellrat</code> properties from <var>x_1</var>, &hellip;, <var>x_n</var>.
</p>
<div class=categorybox>
Categories:<a href="maxima_424.html#Category_003a-Polynomials">Polynomials</a>
&middot;<a href="maxima_424.html#Category_003a-Rational-expressions">Rational expressions</a>
&middot;</div></dd></dl>

<hr>
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<p>
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