Table of Contents

Syntax

float atan(float $angle)

(PHP 4, PHP 5)

$angle The angle parameter which is measured in radians (should be a value between -PI/2 and PI/2.
RETURNS The arc tangent for the angle parameter specified.

What it Does

This function computes the arc tangent for the argument $angle. The result of this trigonometry function can be any real number.

Example

// compute the arc tangent for the angle 1.4 radians
echo 'atan(1.4) = ' . atan(1.4);