ACOS(3) 		   Linux Programmers Manual		      ACOS(3)



NAME
       acos, acosf, acosl - arc cosine function

SYNOPSIS
       #include 

       double acos(double x);
       float acosf(float x);
       long double acosl(long double x);

       Link with -lm.

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
       SVr4, POSIX.1-2001, 4.3BSD, C89, C99.  The float and long double  vari
       ants are C99 requirements.

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

COLOPHON
       This  page  is  part of release 3.05 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



				  2004-10-06			       ACOS(3)