Math.expm1()

The Math.expm1() function returns ex - 1, where x is the argument, and e the base of the natural logarithms.

Syntax

Math.expm1(x)

Parameters

x
A number.

Return value

A number representing ex - 1, where e is Euler's number and x is the argument.

Description

Because expm1() is a static method of Math, you always use it as Math.expm1(), rather than as a method of a Math object you created (Math is not a constructor).

Polyfill

This can be emulated with the help of the Math.exp() function:

Math.expm1 = Math.expm1 || function(x) {
  return Math.exp(x) - 1;
};

Examples

Using Math.expm1()

Math.expm1(-1); // -0.6321205588285577
Math.expm1(0);  // 0
Math.expm1(1);  // 1.718281828459045

Specifications

Specification
ECMAScript (ECMA-262)
The definition of 'Math.expm1' in that specification.

Browser compatibility

DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
expm1Chrome 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

Full support
Full support
No support
No support

See also