# Python math function | sqrt()

• Difficulty Level : Basic
• Last Updated : 11 Jan, 2018

sqrt() function is an inbuilt function in Python programming language that returns the square root of any number.

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```Syntax:
math.sqrt(x)

Parameter:
x is any number such that x>=0

Returns:
It returns the square root of the number
passed in the parameter. ```
 `# Python3 program to demonstrate the ``# sqrt() method `` ` `# import the math module ``import` `math `` ` `# print the square root of  0 ``print``(math.sqrt(``0``)) `` ` `# print the square root of 4``print``(math.sqrt(``4``)) `` ` `# print the square root of 3.5``print``(math.sqrt(``3.5``)) `

Output:

```0.0
2.0
1.8708286933869707
```

Error: When x<0 it does not executes due to a runtime error.

 `# Python3 program to demonstrate the error in ``# sqrt() method `` ` `# import the math module ``import` `math `` ` `# print the error when x<0 ``print``(math.sqrt(``-``1``)) `

Output:

```Traceback (most recent call last):
File "/home/67438f8df14f0e41df1b55c6c21499ef.py", line 8, in
print(math.sqrt(-1))
ValueError: math domain error
```

Practical Application : Given a number, check if its prime or not.
Approach: Run a loop from 2 to sqrt(n) and check if any number in range (2-sqrt(n)) divides n.

 `# Python program for practical application of sqrt() function`` ` `# import math module``import` `math`` ` `# function to check if prime or not ``def` `check(n):``    ``if` `n ``=``=` `1``:``        ``return` `False``         ` `        ``# from 1 to sqrt(n) ``    ``for` `x ``in` `range``(``2``, (``int``)(math.sqrt(n))``+``1``):``        ``if` `n ``%` `x ``=``=` `0``:``            ``return` `False` `    ``return` `True`` ` `# driver code``n ``=` `23``if` `check(n):``    ``print``(``"prime"``) ``else``:``    ``print``(``"not prime"``)`

Output:

```prime
```

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