ATAN(3) | Library Functions Manual | ATAN(3)

# NAME

`atan`, `atanf`, `atanl` — arc tangent functions of one variable

# SYNOPSIS

Math Library (libm, -lm)
`#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 ALSO

acos(3), asin(3), atan2(3), cos(3), cosh(3), sin(3), sinh(3), tan(3), tanh(3)

June 7, 2025 | Debian