DragonFly On-Line Manual Pages


ACOS(3) 	      DragonFly Library Functions Manual	       ACOS(3)

NAME

acos, acosf, acosl -- arc cosine functions

LIBRARY

Math Library (libm, -lm)

SYNOPSIS

#include <math.h> double acos(double x); float acosf(float x); long double acosl(long double x);

DESCRIPTION

The acos(), acosf(), and acosl() functions compute the principal value of the arc cosine of x.

RETURN VALUES

These functions return the arc cosine in the range [0, pi] radians. If: |x| > 1, acos(x) raises an invalid exception and returns an NaN.

SEE ALSO

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

STANDARDS

The acos(), acosf(), and acosl() functions conform to ISO/IEC 9899:1999 (``ISO C99''). DragonFly 4.1 December 21, 2011 DragonFly 4.1