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PHP | sqrt( ) Function
  • Difficulty Level : Expert
  • Last Updated : 23 Nov, 2020

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




<?php
 
echo(sqrt(25));
 
?>

Output: 

5
  • When a negative number is passed as a parameter:

PHP




<?php
 
echo(sqrt(-25));
 
?>

Output: 

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

PHP




<?php
 
echo(sqrt(0.09));
 
?>

Output: 

0.3
  • When zero is passed as a parameter:

PHP




<?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
 

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