{{alias}}( x )
    Computes the value of `cos(πx)`.

    This function computes `cos(πx)` more accurately than the obvious approach,
    especially for large `x`.

    Parameters
    ----------
    x: number
        Input value.

    Returns
    -------
    y: number
        Function value.

    Examples
    --------
    > var y = {{alias}}( 0.0 )
    1.0
    > y = {{alias}}( 0.5 )
    0.0
    > y = {{alias}}( 0.1 )
    ~0.951
    > y = {{alias}}( NaN )
    NaN

    See Also
    --------