# math.atan2()

 Type Function Library math.* Return value Number Revision Release 2021.3646 Keywords atan2, arc tangent See also math.atan()math.tan()

## Overview

Returns the arc tangent of `y/x` (in radians), but uses the signs of both parameters to find the quadrant of the result. It also correctly handles the case of `x` being `0`.

The result will be in the interval `[-pi,+pi]` radians.

This function is useful when converting rectangular coordinates to polar coordinates. `math.atan2()` uses the sign of both arguments to place the result into the correct quadrant, and also produces correct values when one of its arguments is `0` or very close to `0`.

## Syntax

`math.atan2( y, x )`
##### y (required)

Number. A number representing the y coordinate.

##### x (required)

Number. A number representing the x coordinate.

## Examples

```print(math.atan2(1, 0))     -->  pi/2
print(math.atan2(-1, 0))    -->  -pi/2
print(math.atan2(0, 1))     -->  0
print(math.atan2(0, -1))    -->  pi```