{{alias}}( x )
    Computes the hyperbolic arccosine of a number.

    If `x < 1`, the function returns `NaN`.

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

    Returns
    -------
    y: number
        Hyperbolic arccosine (in radians).

    Examples
    --------
    > var y = {{alias}}( 1.0 )
    0.0
    > y = {{alias}}( 2.0 )
    ~1.317
    > y = {{alias}}( NaN )
    NaN

    See Also
    --------