ATAN(3) OpenBSD Programmer's Manual ATAN(3)NAME
atan, atanf, atanl - arc tangent functions of one variable
SYNOPSIS
#include <math.h>
double
atan(double x);
float
atanf(float x);
long double
atanl(long double x);
DESCRIPTION
The atan() function computes the principal value of the arc tangent of x
in the range [-pi/2, +pi/2]. The atanf() function is a single precision
version of atan(). The atanl() function is an extended precision version
of atan().
SEE ALSOacos(3), asin(3), atan2(3), cos(3), cosh(3), math(3), sin(3), sinh(3),
tan(3), tanh(3)OpenBSD 4.9 December 12, 2008 OpenBSD 4.9