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# Javascript Math - atan2 Method

## 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:

- x and y : Numbers.

## 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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