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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).

Examples

Using Math.expm1()

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

Polyfill

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

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

Specifications

Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Math.expm1' in that specification.
Standard Initial definition.
ECMAScript Latest Draft (ECMA-262)
The definition of 'Math.expm1' in that specification.
Draft  

Browser compatibility

FeatureChromeFirefoxEdgeInternet ExplorerOperaSafari
Basic Support3825(Yes)(No)257.1
FeatureAndroidChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic Support(Yes)(Yes)(Yes)25(No)(Yes)8

See also

Document Tags and Contributors

 Last updated by: fscholz,