## Example

`

     float atan2 ( float $y , float $x )

`

## Description

This function calculates the arc tangent of the two variables x and y. It is similar to calculating the arc tangent of y / x, except that the signs of both arguments are used to determine the quadrant of the result. The function returns the result in radians, which is between -PI and PI (inclusive).

## Return Values

The arc tangent of y/x in radians.