JavaScript | Math.atan2( )

The Math.atan2() function in JavaScript is used to return the arctangent of the quotient of its arguments. The Math.atan2() method returns a numeric value between -Π and Π representing the angle theta of an (x, y) point and positive x axis. This is the counterclockwise angle, measured in radians, between the positive X axis, and the point (x, y).

Syntax:

Math.atan2(value1, value2)

Parameters: This function accepts two parameters value1 and value2. value1 represents the y-coordintae and value2 represents x-coordinate of the point (x,y).

Return Value: It returns the arctangent of the quotient of its arguments.

Examples:

Input : Math.atan2(90, 15);  
Output : 1.4056476493802699

Input : Math.atan2(15, 90);
Output : 0.16514867741462683

Below programs illustrate the Math.atan2() function in JavaScript:

1. When y-coordinate is greater than x-coordinate:

   <script type="text/javascript">    document.write(Math.atan2(90, 15));   </script>

   Output:

   1.4056476493802699

2. When y-coordinate is smaller than x-coordinate

   <script type="text/javascript">    document.write(Math.atan2(15, 90));   </script>

   Output:

   0.16514867741462683