===== Syntax =====

<code php>
float atan2(float $y, float $x)
</code>

//(PHP 4, PHP 5)//

^ $y | Numerator of a fraction (y / x) which is the argument for the arc tangent. |
^ $x | Numerator of a fraction (y / x) which is the argument for the arc tangent. |
^ RETURNS | The arc tangent of the fraction (**$y** / **$x**).  This result will be between -PI and PI. |

===== What it Does =====

This function computes the arc tangent for the arguments **$y** and **$x** which represent the numerator and denominator of the fraction (y / x).  The result of this trigonometry function is a value between -PI and PI where PI is roughly (3.14.15926).

===== Example =====

<code php>
// compute the inverse hyperbolic sine for 1.4 radians
echo 'atan2(1.4, 2.0) = ' . atan2(1.4, 2.0);
</code>