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How to calculate the square root of a number in Python

How to calculate the square root of a number in Python.

Here's a step-by-step tutorial on how to calculate the square root of a number in Python:

Step 1: Import the math module​

First, you need to import the math module in Python. The math module provides various mathematical functions, including the square root function.

import math

Step 2: Use the math.sqrt() function​

To calculate the square root of a number, you can use the math.sqrt() function from the math module. This function takes a single argument, which is the number whose square root you want to calculate, and returns the square root as a floating-point number.

number = 16
sqrt = math.sqrt(number)
print("The square root of", number, "is", sqrt)

Output:

The square root of 16 is 4.0

Step 3: Handling negative numbers​

The math.sqrt() function works only with positive numbers. If you try to calculate the square root of a negative number, it will raise a ValueError. To handle this, you can use a conditional statement to check if the number is positive before calculating the square root.

number = -16
if number >= 0:
    sqrt = math.sqrt(number)
    print("The square root of", number, "is", sqrt)
else:
    print("Cannot calculate the square root of a negative number")

Output:

Cannot calculate the square root of a negative number

Step 4: Handling user input​

You can also calculate the square root of a number provided by the user. To do this, you can use the input() function to get the number from the user as a string, and then convert it to a float before calculating the square root.

number = float(input("Enter a number: "))
if number >= 0:
    sqrt = math.sqrt(number)
    print("The square root of", number, "is", sqrt)
else:
    print("Cannot calculate the square root of a negative number")

Output:

Enter a number: 25
The square root of 25.0 is 5.0

That's it! You now know how to calculate the square root of a number in Python using the math module.