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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 );
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 variants are C99 requirements.
SEE ALSO
asin (3) atan (3)
atan2 (3) cacos (3) cos (3) sin (3) tan
(3)
