atanpi3
Half-cycle arc tangent functions
Usage
#include <math.h>
double
atanpi(double x);
float
atanpif(float x);
long double
atanpil(long double x);
Library
Math Library (libm, -lm)
Overview
The atanpi(), atanpif(), and atanpil() functions compute the principal value of the arc tangent of x, divided by , thus measuring the angle in half-cycles.
Return values
The atanpi(), atanpif(), and atanpil()
functions return values in the range [-1/2, +1/2].