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

<p> <strong><code>Math.sqrt()</code></strong> 함수는 숫자의 제곱근을 반환합니다.</p>

<p><math display="block"><semantics><mrow><mo>∀</mo><mi>x</mi><mo>≥</mo><mn>0</mn><mo>,</mo><mstyle mathvariant="monospace"><mrow><mi>M</mi><mi>a</mi><mi>t</mi><mi>h</mi><mo>.</mo><mi>s</mi><mi>q</mi><mi>r</mi><mi>t</mi><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></mrow></mstyle><mo>=</mo><msqrt><mi>x</mi></msqrt><mo>=</mo><mtext>the unique</mtext><mspace width="thickmathspace"></mspace><mi>y</mi><mo>≥</mo><mn>0</mn><mspace width="thickmathspace"></mspace><mtext>such that</mtext><mspace width="thickmathspace"></mspace><msup><mi>y</mi><mn>2</mn></msup><mo>=</mo><mi>x</mi></mrow><annotation encoding="TeX">\forall x \geq 0, \mathtt{Math.sqrt(x)} = \sqrt{x} = \text{the unique} \; y \geq 0 \; \text{such that} \; y^2 = x</annotation></semantics></math></p>

<h2 id="문법">문법</h2>

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

<h3 id="매개변수">매개변수</h3>

<dl>
 <dt><code>x</code></dt>
 <dd>숫자.</dd>
</dl>

<h3 id="반환_값">반환 값</h3>

<p>주어진 숫자에 루트(<strong>√ </strong>)를 씌웁니다. 만약 숫자가 음수이면 {{jsxref("NaN")}}를 반환합니다.</p>

<h2 id="설명">설명</h2>

<p>만약 <code>x</code> 가 음수라면 <code>Math.sqrt()</code> 함수는 {{jsxref("NaN")}}를 반환합니다.</p>

<p><code>sqrt()</code>는 <code>Math</code>의 정적 메서드 이므로 만든  <code>Math</code> 객체의 메서드가 아니라 항상 <code>Math.sqrt()</code>함수를 사용해야합니다. (<code>Math</code>는 생성자가 없습니다.)</p>

<h2 id="예제">예제</h2>

<h3 id="Math.sqrt()"> <code>Math.sqrt()</code></h3>

<pre class="brush: js">Math.sqrt(9); // 3
Math.sqrt(2); // 1.414213562373095

Math.sqrt(1);  // 1
Math.sqrt(0);  // 0
Math.sqrt(-1); // NaN
</pre>

<h2 id="표준">표준</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">표준</th>
   <th scope="col">상태</th>
   <th scope="col">비고</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-15.8.2.17', 'Math.sqrt')}}</td>
   <td>{{Spec2('ES5.1')}}</td>
   <td> </td>
  </tr>
  <tr>
   <td>{{SpecName('ES6', '#sec-math.sqrt', 'Math.sqrt')}}</td>
   <td>{{Spec2('ES6')}}</td>
   <td> </td>
  </tr>
  <tr>
   <td>{{SpecName('ESDraft', '#sec-math.sqrt', 'Math.sqrt')}}</td>
   <td>{{Spec2('ESDraft')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="브라우저_호환성">브라우저 호환성</h2>

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

<h2 id="참조">참조</h2>

<ul>
 <li>{{jsxref("Math.cbrt()")}}</li>
 <li>{{jsxref("Math.exp()")}}</li>
 <li>{{jsxref("Math.log()")}}</li>
 <li>{{jsxref("Math.pow()")}}</li>
</ul>