acos()

Computes the arc value of cosine.

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

Parameter

x

A floating-point value, in the range of -1.0 to 1.0.

Remarks

These functions return the arccosine of the argument x, in radians from 0 to pi. If x is not in the range of -1.0 to 1.0 then these functions set errno to EDOM and

  fpclassify(acos(x))

returns FP_NAN.

This facility may not be available on configurations of the EWL that run on platforms that do not have floating-point math capabilities.