Calculates the arccosine of a double value.

#include <math.h>

double acos (double x);

Parameters

x

Value whose arccosine is calculated. Must be between -1 and 1.

Return Values

The arccosine result in the range 0 (zero) to p radians.

Success.

0 (zero) if x is less than -1 or greater than 1; the function sets errno to EDOM and prints a DOMAIN error message to stderr.

Failure.

Note:   This function does not return standard ANSI domain or range errors.

Requirements

See Also

asin, atan, cos, matherr, sin, tan