# atan(3) [opendarwin man page]

```ATAN(3) 						   BSD Library Functions Manual 						   ATAN(3)

NAME
atan -- arc tangent function of one variable

SYNOPSIS
#include <math.h>

double
atan(double x);

DESCRIPTION
The atan() function computes the principal value of the arc tangent of x in the range [-pi/2, +pi/2].

SPECIAL VALUES
atan(+-0) returns +-0.

atan(+-infinity) returns +-pi/2

acos(3), asin(3), atan2(3), cos(3), cosh(3), sin(3), sinh(3), tan(3), tanh(3), math(3), matherr(3) The atan() function conforms to ISO/IEC
9899:1999(E).

BSD								 November 18, 2002							       BSD```

## Check Out this Related Man Page

```ATAN(3) 						   BSD Library Functions Manual 						   ATAN(3)

NAME
atan -- arc tangent function of one variable

SYNOPSIS
#include <math.h>

double
atan(double x);

long double
atanl(long double x);

float
atanf(float x);

DESCRIPTION
The atan() function computes the principal value of the arc tangent of x.	The result is in the range [-pi/2, +pi/2].

SPECIAL VALUES
atan(+-0) returns +-0.

atan(+-infinity) returns +-pi/2

VECTOR OPERATIONS
If you need to apply the atan() function to SIMD vectors or arrays, using the following functions provided by the Accelerate.framework may
give significantly better performance:

#include <Accelerate/Accelerate.h>

vFloat vatanf(vFloat x);
void vvatanf(float *y, const float *x, const int *n);
void vvatan(double *y, const double *x, const int *n);

acos(3), asin(3), atan2(3), cos(3), cosh(3), sin(3), sinh(3), tan(3), tanh(3), math(3) The atan() function conforms to ISO/IEC 9899:2011.

BSD								 December 11, 2006							       BSD```
Man Page

## Satan

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## Satan

has anyone had any experience with SATAN? and can fill me in with some quick pro/cons and maybe some screenshots? thanks email removed - read the rules

## usage of atan

Hi All, can anybody explain me the syntax and usage of "atan" command? Thanks in advance.

## Atan2 function in awk

Hello All, I need your help in the following situation. I have a 100x100 matrix with angle values ranging from -180 to 180. I would like to calculate the atan2 values for the above mentioned matrix, and the output should be in the same format (100x100 matrix). I tried the following code: ...