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], radians. If:
|x| > 1,
acos(x) raises an invalid exception and returns an .
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”).