# PHP | sqrt( ) Function

Many a 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 pow() 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:

1. When a positive number is passed as a parameter:

 ` `

Output:

`5`
2. When a negative number is passed as a parameter:

 ` `

Output:

`NaN`
3. When a number with decimal places is passed as a parameter:

 ` `

Output:

```0.3
```
4. When zero is passed as a parameter:
 ` `

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.

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