Math.cbrt()

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

Math.cbrt(x)=x3=the uniqueysuch thaty3=x\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.

Return value

The cube root of the given 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

Using Math.cbrt()

Math.cbrt(NaN); // NaN
Math.cbrt(-1); // -1
Math.cbrt(-0); // -0
Math.cbrt(-Infinity); // -Infinity
Math.cbrt(0); // 0
Math.cbrt(1); // 1
Math.cbrt(Infinity); // Infinity
Math.cbrt(null); // 0
Math.cbrt(2);  // 1.2599210498948732

Polyfill

For all x0x \geq 0, have x3=x1/3\sqrt[3]{x} = x^{1/3} so this can be emulated by the following function:

if (!Math.cbrt) {
  Math.cbrt = (function(pow) {
    return function cbrt(x){
      // ensure negative numbers remain negative:
      return x < 0 ? -pow(-x, 1/3) : pow(x, 1/3);
    };
  })(Math.pow); // localize Math.pow to increase efficiency
}

Specifications

Specification
ECMAScript (ECMA-262)
The definition of 'Math.cbrt' in that specification.

Browser compatibility

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
cbrtChrome Full support 38Edge Full support 12Firefox Full support 25IE No support NoOpera Full support 25Safari Full support 8WebView Android Full support 38Chrome Android Full support 38Firefox Android Full support 25Opera Android Full support 25Safari iOS Full support 8Samsung Internet Android Full support 3.0nodejs Full support 0.12

Legend

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See also