# Math.cbrt()

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

$M a t h . c b r t ( x ) = x 3 = the unique y such that y 3 = x \mathtt{Math.cbrt(x)} = \sqrt[3]{x} = \text{the unique} ; y ; \text{such that} ; y^3 = x$

## Syntax

Math.cbrt(x)


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).

## Polyfill

For all $x \geq 0$, have $\sqrt\left[3\right]\left\{x\right\} = x^\left\{1/3\right\}$ 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
}


## 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


## Browser compatibility

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