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

<p><strong><code>Math.pow()</code></strong> 函式回傳 <code>base</code> 的 <code>exponent</code> 次方（幂）值，也就是 <code>base<sup>exponent</sup></code>。</p>

<h2 id="語法">語法</h2>

<pre class="syntaxbox notranslate"><code>Math.pow(<var>base</var>, <var>exponent</var>)</code></pre>

<h3 id="參數">參數</h3>

<dl>
 <dt><code>base</code></dt>
 <dd>基數。</dd>
 <dt><code>exponent</code></dt>
 <dd>要乘上 <code>base</code> 幾次的指數。</dd>
</dl>

<h3 id="回傳值">回傳值</h3>

<p>A number representing the given base taken to the power of the given exponent.</p>

<h2 id="敘述">敘述</h2>

<p>The <strong><code>Math.pow()</code></strong> function returns the <code>base</code> to the <code>exponent</code> power, that is, <code>base<sup>exponent</sup></code>, the base and the exponent are in decimal numeral system.</p>

<p>由於 <code>pow()</code> 是 <code>Math</code> 的靜態方法，you always use it as <code>Math.pow()</code>, rather than as a method of a <code>Math</code> object you created（<code>Math</code> 並沒有建構子）。</p>

<h2 id="示例">示例</h2>

<h3 id="使用_Math.pow">使用 <code>Math.pow()</code></h3>

<pre class="brush: js notranslate">// simple
Math.pow(7, 2);    // 49
Math.pow(7, 3);    // 343
Math.pow(2, 10);   // 1024
// fractional exponents
Math.pow(4, 0.5);  // 2 （4 的平方根）
Math.pow(8, 1/3);  // 2 （8 的立方根）
Math.pow(2, 0.5);  // 1.4142135623730951 （2 的平方根）
Math.pow(2, 1/3);  // 1.2599210498948732 （2 的立方根）
// signed exponents
Math.pow(7, -2);   // 0.02040816326530612 (1/49)
Math.pow(8, -1/3); // 0.5
// signed bases
Math.pow(-7, 2);   // 49 (負負得正，2次方都是正數)
Math.pow(-7, 3);   // -343 (3次方有可能為負數)
Math.pow(-7, 0.5); // NaN (負數沒辦法得出一個實數平方根)
// due to "even" and "odd" roots laying close to each other,
// and limits in the floating number precision,
// negative bases with fractional exponents always return NaN
Math.pow(-7, 1/3); // NaN
</pre>

<h2 id="規範">規範</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">規範</th>
   <th scope="col">狀態</th>
   <th scope="col">註解</th>
  </tr>
  <tr>
   <td>{{SpecName('ES1')}}</td>
   <td>{{Spec2('ES1')}}</td>
   <td>Initial definition. Implemented in JavaScript 1.0.</td>
  </tr>
  <tr>
   <td>{{SpecName('ES5.1', '#sec-15.8.2.13', 'Math.pow')}}</td>
   <td>{{Spec2('ES5.1')}}</td>
   <td></td>
  </tr>
  <tr>
   <td>{{SpecName('ES6', '#sec-math.pow', 'Math.pow')}}</td>
   <td>{{Spec2('ES6')}}</td>
   <td></td>
  </tr>
  <tr>
   <td>{{SpecName('ESDraft', '#sec-math.pow', 'Math.pow')}}</td>
   <td>{{Spec2('ESDraft')}}</td>
   <td></td>
  </tr>
 </tbody>
</table>

<h2 id="瀏覽器相容性">瀏覽器相容性</h2>

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

<h2 id="參見">參見</h2>

<ul>
 <li>{{jsxref("Math.cbrt()")}}</li>
 <li>{{jsxref("Math.exp()")}}</li>
 <li>{{jsxref("Math.log()")}}</li>
 <li>{{jsxref("Math.sqrt()")}}</li>
 <li><a href="https://developer.mozilla.org/zh-TW/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators#Exponentiation" title="Arithmetic operators take numerical values (either literals or variables) as their operands and return a single numerical value. The standard arithmetic operators are addition (+), subtraction (-), multiplication (*), and division (/).">Exponentiation operator</a> {{experimental_inline}}</li>
</ul>