ACOS(S)             Linux Programmer's Manual             ACOS(S)



NAME
       acos - arc cosine function

SYNOPSIS
       #include <math.h>

       double acos(double x);

DESCRIPTION
       The  acos()  function calculates the arc cosine of x; that
       is the value whose cosine is x.  If x  falls  outside  the
       range -1 to 1, acos() fails and errno is set.

RETURN VALUE
       The  acos() function returns the arc cosine in radians and
       the value is mathematically defined to be between 0 and PI
       (inclusive).

ERRORS
       EDOM   x is out of range.

CONFORMING TO
       SVID 3, POSIX, BSD 4.3, ISO 9899

SEE ALSO
       asin(n), atan(n), atan2(2), cos(s), sin(n), tan(n)



                            1993-06-08                    ACOS(S)