JavaScript Math.cbrt(): Complete Guide

JavaScript Math.cbrt() method is used to find the cube root of any number. The Math.cbrt() method comes in handy in several programs involving mathematical calculations. The cbrt() is a static method of Math, and it can be used without creating an object.

JavaScript Math cbrt()

Javascript Math.cbrt() function is a built-in function that is used to find the cube root of a number. The Math.cbrt() function accepts a single parameter, which is simply a number whose cube root needs to find. It returns a cube root of the given number.

Syntax

Math.cbrt(x)

Parameter(s)

The variable x, whose cube root value is to be determined.

Return Value

The cube root value.

Polyfill

Math.cbrt = Math.cbrt || function(x) {
      return Math.round(x<0?-Math.pow(-x,1/3):Math.pow(x,1/3));
};

See the following figure.

 

Note

1. For a positive finite argument x, cbrt(-x) gives the same value as -cbrt(x).
2. If the argument is negative infinity, then this method returns negative infinity.
3. If the argument is positive infinity, then this method returns positive infinity.
4. If the argument is positive zero or negative zero, then this method returns the same value that is passed.
5. If the passed value is not a valid number, the method returns NaN.
6. If the passed value is null, the method returns 0.

Compatibility(Version and above)

1. Google Chrome v38
2. Firefox v25
3. Edge v12
4. Opera v25 
5. Safari v8
6. Android webview 
7. Chrome for Android v38
8. Firefox for Android v25
9. Opera for Android 
10. Safari on iOS v8
11. Samsung Internet
12. Node.js v0.12

Non-compatible with: Internet Explorer 

JavaScript version: ECMAScript 6

JavaScript cbrt() example

The following code demonstrates the use of a JS cbrt() method.

See the following code.

// example1.js

var a = 8;
var b = 27;
var c = 64;
var d = -64;

console.log(Math.cbrt(a));
console.log(Math.cbrt(b));
console.log(Math.cbrt(c));
console.log(Math.cbrt(d));

Output

node example1
2
3
4
-4

Example 2

The following example demonstrates a case where the values other than valid numbers are passed.

//example2.js

var a = "Hello, world";
var b;

console.log(Math.cbrt(a));
console.log(Math.cbrt(b));

Output

node example2
NaN
NaN

Example 3

The js cbrt() method cannot be used with complex arguments as only integer arguments are accepted.

// example3.js

// Complex values cannot be passed as arguments as follows
// Since only integer arguments are accepted.

console.log(Math.cbrt(2 + i));

Output

node example3
ReferenceError: i is not defined

Example 4

The following example demonstrates a use of polyfill for the Javascript cbrt() method.

// example4.js

var a = 8;
var b = 27;
var c = 64;
var d = -64;

function polyfill(x) {
  return Math.round(x < 0 ? -Math.pow(-x, 1 / 3) : Math.pow(x, 1 / 3));
}

console.log(Math.cbrt(a));
console.log(Math.cbrt(b));
console.log(Math.cbrt(c));
console.log(Math.cbrt(d));
console.log();

console.log(polyfill(a));
console.log(polyfill(b));
console.log(polyfill(c));
console.log(polyfill(d));

Output

node example4
2
3
4
-4

2
3
4
-4

Example 5

The following example demonstrates that for positive finite argument x,

The cbrt(-x) gives the same value as -cbrt(x).

See the following code.

//example5.js

var x = 125;

console.log(Math.cbrt(-x));
console.log(-Math.cbrt(x));

Output

node example5
5
5

Example 6

The following example demonstrates that if negative infinity is passed as an argument, then the cbrt() method returns negative infinity.

See the following code.

// example6.js

var a = Number.NEGATIVE_INFINITY;

console.log(Math.cbrt(a));

Output

node example6
Infinity

Example 7

The following example demonstrates that if positive infinity is passed as an argument, then this method returns positive infinity.

// example7.js

var a = Number.POSITIVE_INFINITY;

console.log(Math.cbrt(a));

Output

node example7
Infinity

Example 8

The following example demonstrates that if positive or negative zero is passed as an argument, then this method returns zero with the same sign as the argument.

// example8.js

var a = 0;
var b = -0;

console.log(Math.cbrt(a));
console.log(Math.cbrt(b));

Output

node example8
0
-0

Example 9

The following example demonstrates that if null is passed as an argument, then this method returns 0.

// example9.js

var a = null;
var b = "";
var c = [];

console.log(Math.cbrt(a));
console.log(Math.cbrt(b));
console.log(Math.cbrt(c));

Output

node example9
0
0
0

See also

Javascript Math.log()

Javascript Math.acos()

Javascript Math.asin()

Javascript Math.acosh()

Javascript Math.asinh()