NAME
atan, atanf — arc tangent function of one variable
SYNOPSIS
#include <math.h>double
atan(double x);
float
atanf(float x);
DESCRIPTION
The atan() and atanf() functions compute the principal value of the arc tangent of x in the range [-π/2, +π/2].
STANDARDS
The atan() functions conforms to ANSI X3.159-1989 (“ANSI C”).