ACOS

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 fBacos()fP function calculates the arc cosine of fIxfP; that is the value whose cosine is fIxfP. If fIxfP falls outside the range -1 to 1, fBacos()fP fails and fIerrnofP is set.

RETURN VALUE

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

ERRORS

EDOM: fIxfP is out of range.

CONFORMING TO

SVID 3, POSIX, BSD 4.3, ISO 9899. The float and long double variants are C99 requirements.