# Python : Find the Square Root

Tutorial by:Rizwan Abdullah      Date: 2016-06-16 00:38:35

## 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.

## Python

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