Example: For positive numbers
# Python Program to calculate the square root
# Note: change this value for a different result
num = 8
# To take the input from the user
#num = float(input('Enter a number: '))
num_sqrt = num ** 0.5
print('The square root of %0.3f is %0.3f'%(num ,num_sqrt))
Output
The square root of 8.000 is 2.828
In this program, we store the number in num and find the square root using the ** exponent operator. This program works for all positive real numbers. But for negative or complex numbers, it can be done as follows.
Source code: For real or complex numbers
# Find square root of real or complex numbers
# Importing the complex math module
import cmath
num = 1+2j
# To take input from the user
#num = eval(input('Enter a number: '))
num_sqrt = cmath.sqrt(num)
print('The square root of {0} is {1:0.3f}+{2:0.3f}j'.format(num ,num_sqrt.real,num_sqrt.imag))
Output
The square root of (1+2j) is 1.272+0.786j
In this program, we use the sqrt() function in the cmath (complex math) module.
Note: If we want to take complex number as input directly, like 3+4j, we have to use the eval() function instead of float().
The eval() method can be used to convert complex numbers as input to the complex objects in Python. To learn more, visit Python eval() function.
Also, notice the way in which the output is formatted. To learn more, visit string formatting in Python.