PHP sqrt( ) Function

Many times it happens that while solving mathematical expressions we require to calculate the square root of a number. 
To solve this issue like other programming language PHP provides us with a built-in function sqrt() which can be used to calculate the square root of a number. The sqrt() function in PHP is used to calculate the square root of a number. 
We already have discussed about sqrt() function in brief in the article PHP | Math functions. In this article we will learn about the sqrt() function in details.

Syntax:  

float sqrt(value)

Parameters: This function accepts a single parameter $value. It is the number whose square root you want to know.

Return Value: It returns a floating-point value which is the square root of the argument $value passed to it.

Examples: 

Input : sqrt(25) 
Output : 5

Input : sqrt(-25) 
Output : NaN

Input : sqrt(0.09) 
Output :0.3

Input : sqrt(0)
Output : 0

Below programs illustrate the working of sqrt() in PHP: 

• When a positive number is passed as a parameter:

<?php

echo(sqrt(25));

?>

Output: 

5

• When a negative number is passed as a parameter:

<?php

echo(sqrt(-25));

?>

Output: 

NaN

• When a number with decimal places is passed as a parameter:

<?php

echo(sqrt(0.09));

?>

Output: 

0.3

• When zero is passed as a parameter:

<?php

echo(sqrt(0));

?>

Output:

0

Important Points To Note: 

• sqrt() function is used to calculate the square root of a number.
• It is much more efficient than the generic method of square root calculation.
• Precision depends on the user's precision directive.

Reference: 
http://php.net/manual/en/function.sqrt.php