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# Python math function | sqrt()

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

```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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