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Javascript Math - atan2 Method

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Description:

This method returns the arctangent of the quotient of its arguments. The atan2 method returns a numeric value between -pi and pi representing the angle theta of an (x,y) point.

Syntax:

Math.atan2( x, y ) ;

Here is the detail of parameters:

Return Value:

Returns the arctangent in radians of a number.

Math.atan2( ±0, -0 ) returns ±PI.
Math.atan2( ±0, +0 ) returns ±0.
Math.atan2( ±0, -x ) returns ±PI for x < 0.
Math.atan2( ±0, x ) returns ±0 for x > 0.
Math.atan2( y, ±0 ) returns -PI/2 for y > 0.
Math.atan2( ±y, -Infinity ) returns ±PI for finite y > 0.
Math.atan2( ±y, +Infinity ) returns ±0 for finite y > 0.
Math.atan2( ±Infinity, +x ) returns ±PI/2 for finite x.
Math.atan2( ±Infinity, -Infinity ) returns ±3*PI/4.
Math.atan2( ±Infinity, +Infinity ) returns ±PI/4.

Example:

<html>
<head>
<title>JavaScript Math atan2() Method</title>
</head>
<body>
<script type="text/javascript">

var value = Math.atan2(90,15);
document.write("First Test Value : " + value ); 
  
var value = Math.atan2(15,90);
document.write("<br />Second Test Value : " + value ); 

var value = Math.atan2(0, -0);
document.write("<br />Third Test Value : " + value ); 

var value = Math.atan2(+Infinity, -Infinity);
document.write("<br />Fourth Test Value : " + value ); 
</script>
</body>
</html>

This will produce following result:

First Test Value : 1.4056476493802698
Second Test Value : 0.16514867741462683
Third Test Value : 3.141592653589793
Fourth Test Value : 2.356194490192345 

To understand it in better way you can Try it yourself.


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