Find the Square Root

Source Code

# Python Program to calculate the square root

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

Enter a number: 8
The square root of 8.000 is 2.828

In this program, we ask the user for a number 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.

# Find square root of real or complex numbers
# Import the complex math module
import cmath

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

Enter a number: 1+2j
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. Notice that we have used the eval() function instead of float() to convert complex number as well. Also notice the way in which the output is formatted. Look here for more about string formatting in Python.