JavaScript Math.sqrt() Examples [In-Depth Tutorial]

Using the Math.sqrt() method in JavaScript

Math.sqrt() is a built-in function in JavaScript that returns the square root of a given number. The function takes one argument, which is the number to be square rooted.

The syntax for using Math.sqrt() is as follows:

Math.sqrt(number)

where number is the number you want to find the square root of.

For example, to find the square root of 25, you would write:

Math.sqrt(25) // returns 5

Note that the Math.sqrt() function returns a NaN (Not a Number) value if the argument passed to it is negative.

Example 1: Normal Square Root Calculation

To find the square root of 16 using math.sqrt() method, you can use the following code:

let x = 16;
let result = Math.sqrt(x);
console.log(result);

Output

4

Example 2: Square Root of a Decimal Value

To find the square root of a decimal using Math.sqrt() method, you can use the following code:

let num = 2.25;
let squareRoot = Math.sqrt(num);
console.log(squareRoot);

Output

1.5

Example 3: Calculating the distance between two points in a 2D plane

To calculate the distance between two points (x1, y1) and (x2, y2) in a 2D plane, you can use the following formula:

let x1 = 1;
let y1 = 2;
let x2 = 4;
let y2 = 6;
let distance = Math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2);
console.log(distance);

Output

5

Here, we are using the Math.sqrt() method to calculate the square root of the sum of the squares of the differences between the x and y coordinates of the two points.

Example 4: Calculating the standard deviation of an array of numbers

To calculate the standard deviation of an array of numbers, you can use the following formula:

let numbers = [2, 4, 6, 8, 10];
let sum = numbers.reduce((acc, val) => acc + val, 0);
let mean = sum / numbers.length;
let variance =
    numbers.reduce((acc, val) => acc + (val - mean) ** 2, 0) /
    (numbers.length - 1);
let stdDev = Math.sqrt(variance);
console.log(stdDev);

Output

3.1622776601683795

Here, we are using the Math.sqrt() method to calculate the square root of the variance of the array of numbers.

Summary

The Math.sqrt() method is a built-in method in JavaScript that is used to calculate the square root of a number, and is part of the Math object in JavaScript. With the Math.sqrt() method, we can carry out a ton of mathematical operations involve square roots from standard deviation to distance between two points.

References

Math.sqrt() - JavaScript | MDN (mozilla.org)