PHP sqrt() Function

Return the square root of different numbers:

<?php
echo(sqrt(0) . "<br>");
echo(sqrt(1) . "<br>");
echo(sqrt(9) . "<br>");
echo(sqrt(0.64) . "<br>");
echo(sqrt(-9));
?>

Definition and Usage

The sqrt() function returns the square root of a number.

sqrt( number);

Parameter	Description
number	Required. Specifies a number

Return Value:	The square root of number, or NAN for negative numbers
Return Type:	Float
PHP Version:	4+