PHP atan2() Function

Example

Return the arc tangent of two variables with the atan2() function:

<?php
echo(atan2(0.50,0.50) . " ");
echo(atan2(-0.50,-0.50) . " ");
echo(atan2(5,5) . " ");
echo(atan2(10,20) . " ");
echo(atan2(-5,-5) . " ");
echo(atan2(-10,10));
?>

Try it Yourself »

Definition and Usage

The atan2() function returns the arc tangent of y/x, in radians. Where x and y are the coordinates of a point (x,y).

Syntax

atan2(y,x);

Parameter Values

Parameter	Description
y	Required. Specifies a positive or negative number
x	Required. Specifies a positive or negative number

Technical Details

Return Value:	The arc tangent of y/x in radians, which is between -PI and PI
Return Type:	Float
PHP Version:	4+

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