---
title: Math.expm1()
slug: Web/JavaScript/Reference/Global_Objects/Math/expm1
translation_of: Web/JavaScript/Reference/Global_Objects/Math/expm1
---
<div>{{JSRef}}</div>

<p>The <strong><code>Math.expm1()</code></strong> function returns <code>e<sup>x</sup> - 1</code>, where <code>x</code> is the argument, and {{jsxref("Math.E", "e", "", 1)}} the base of the natural logarithms.</p>

<div>{{EmbedInteractiveExample("pages/js/math-expm1.html")}}</div>



<h2 id="Syntax">Syntax</h2>

<pre class="syntaxbox notranslate"><code>Math.expm1(<var>x</var>)</code></pre>

<h3 id="Parameters">Parameters</h3>

<dl>
 <dt><code>x</code></dt>
 <dd>Um número.</dd>
</dl>

<h3 id="Return_value">Return value</h3>

<p>Um número representando <code>e<sup>x</sup> - 1</code>, onde <code>e</code> é {{jsxref("Math.E", "Euler's number", "", 1)}} e <code>x</code> ié o argumento.</p>

<h2 id="Description">Description</h2>

<p>Porque <code>expm1()</code> é um método estático de is <code>Math</code>, você sempre o usurá como <code>Math.expm1()</code>, do que como um método de um objeto <code>Math</code> que você criou (<code>Math</code> não é um contrutor).</p>

<h2 id="Polyfill">Polyfill</h2>

<p>This can be emulated with the help of the {{jsxref("Math.exp()")}} function:</p>

<pre class="brush: js notranslate">Math.expm1 = Math.expm1 || function(x) {
  return Math.exp(x) - 1;
};
</pre>

<h2 id="Examples">Examples</h2>

<h3 id="Using_Math.expm1">Using <code>Math.expm1()</code></h3>

<pre class="brush: js notranslate">Math.expm1(-1); // -0.6321205588285577
Math.expm1(0);  // 0
Math.expm1(1);  // 1.718281828459045
</pre>

<h2 id="Specifications">Specifications</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Specification</th>
  </tr>
  <tr>
   <td>{{SpecName('ESDraft', '#sec-math.expm1', 'Math.expm1')}}</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</h2>

<p class="hidden">The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out <a href="https://github.com/mdn/browser-compat-data">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</p>

<p>{{Compat("javascript.builtins.Math.expm1")}}</p>

<h2 id="See_also">See also</h2>

<ul>
 <li>{{jsxref("Math.E")}}</li>
 <li>{{jsxref("Math.exp()")}}</li>
 <li>{{jsxref("Math.log()")}}</li>
 <li>{{jsxref("Math.log10()")}}</li>
 <li>{{jsxref("Math.log1p()")}}</li>
 <li>{{jsxref("Math.log2()")}}</li>
 <li>{{jsxref("Math.pow()")}}</li>
</ul>