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