Real Python: The Python Square Root Function

The Python square root function, sqrt(), is part of the math module and is used to calculate the square root of a given number. To use it, you import the math module and call math.sqrt() with a non-negative number as an argument. For example, math.sqrt(9) returns 3.0.

This function works with both integers and floats and is essential for mathematical operations like solving equations and calculating geometric properties. In this tutorial, you’ll learn how to effectively use the square root function in Python.

By the end of this tutorial, you’ll understand how:

• Python’s sqrt() function calculates square roots using Python’s math.sqrt() for quick and accurate results in your programs.
• math.sqrt() calculates the square root of positive numbers and zero but raises an error for negative inputs.
• Python’s square root function can be used to solve real-world problems like calculating distances using the Pythagorean theorem.

Time to dive in!

Square Roots in Mathematics

In algebra, a square, x, is the result of a number, n, multiplied by itself: x = n²

You can calculate squares using Python:

>>> n=5>>> x=n**2>>> x25

The Python ** operator is used for calculating the power of a number. In this case, 5 squared, or 5 to the power of 2, is 25.

The square root, then, is the number n, which when multiplied by itself yields the square, x.

In this example, n, the square root of 25, is 5.

25 is an example of a perfect square. Perfect squares are the squares of integer values:

>>> 1**21>>> 2**24>>> 3**29

You might have memorized some of these perfect squares when you learned your multiplication tables in an elementary algebra class.

If you’re given a small perfect square, it may be straightforward enough to calculate or memorize its square root. But for most other squares, this calculation can get a bit more tedious. Often, an estimation is good enough when you don’t have a calculator.