ACOS(3) Linux Programmer's Manual ACOS(3)
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(3), atan(3), atan2(3), cos(3), sin(3), tan(3)
1993-06-08 ACOS(3)
