PHP atan() Function

Return the arc tangent of different numbers with the atan() function:

<?php
echo(atan(0.50) . " ");
echo(atan(-0.50) . " ");
echo(atan(5) . " ");
echo(atan(-5) . " ");
echo(atan(100) . " ");
echo(atan(-100));
?>

Definition and Usage

The atan() function returns the arc tangent of arg as a numeric value between -Pi/2 and Pi/2 radians.

atan( arg);

Parameter	Description
arg	Required. Specifies an argument to process

Return Value:	The arc tangent of arg in radians
Return Type:	Float
PHP Version:	4+