ACOS(3)            Linux Programmer's Manual            ACOS(3)





NAME
       acos, acosf, acosl - arc cosine function

SYNOPSIS
       #include <math.h>

       double acos(double x);
       float acosf(float x);
       long double acosl(long 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.  The float and long
       double variants are C99 requirements.

SEE ALSO
       asin(3), atan(3), atan2(3), cos(3), sin(3), tan(3)



                           2002-07-25                   ACOS(3)
