Math.cbrt()

Summary

The Math.cbrt() function returns the cube root of a number, that is

$$\mathtt{Math.cbrt(x)} = \sqrt[3]{x} = \text{the unique} \; y \; \text{such that} \; y^3 = x$$

Syntax

Math.cbrt(x)

Parameters

x

A number.

Description

Because cbrt is a static method of Math, you always use it as Math.cbrt(), rather than as a method of a Math object you created (Math is not a constructor).

Examples

Example: Using Math.cbrt()

Math.cbrt(-1); // -1
Math.cbrt(0);  // 0
Math.cbrt(1);  // 1

Math.cbrt(2);  // 1.2599210498948734

Polyfill

For all $x \geq 0$, have $\sqrt[3]{x} = x^{1/3}$ so this can be emulated by the following function:

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

Specifications

Browser compatibility