NAME    [Toc]    [Back]

     acos, acosf - arc cosine function

LIBRARY    [Toc]    [Back]

     Math Library (libm, -lm)

SYNOPSIS    [Toc]    [Back]

     #include <math.h>

     double
     acos(double x);

     float
     acosf(float x);

DESCRIPTION    [Toc]    [Back]

     The acos() and acosf() functions compute the principal value of the arc
     cosine of x in the range [0, pi].

RETURN VALUES    [Toc]    [Back]

     If |x|>1, acos(x) and acosf(x) set the global variable errno to EDOM.

SEE ALSO    [Toc]    [Back]

     asin(3), atan(3), atan2(3), cos(3), cosh(3), math(3), sin(3), sinh(3),
     tan(3), tanh(3)

STANDARDS    [Toc]    [Back]

     The acos() function conforms to ANSI X3.159-1989 (``ANSI C'').

BSD                               May 2, 1991                              BSD