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diff --git a/files/zh-cn/web/javascript/reference/global_objects/math/asin/index.html b/files/zh-cn/web/javascript/reference/global_objects/math/asin/index.html index 7e6017abbd..2386375e80 100644 --- a/files/zh-cn/web/javascript/reference/global_objects/math/asin/index.html +++ b/files/zh-cn/web/javascript/reference/global_objects/math/asin/index.html @@ -5,23 +5,23 @@ translation_of: Web/JavaScript/Reference/Global_Objects/Math/asin --- <div> {{JSRef("Global_Objects", "Math")}}</div> -<h2 id="Summary" name="Summary">概述</h2> +<h2 id="Summary">概述</h2> <p><code><strong>Math.asin()</strong></code> 方法返回一个数值的反正弦(单位为弧度),即:</p> <p><math display="block"><semantics><mrow><mo>∀</mo><mi>x</mi><mo>∊</mo><mo stretchy="false">[</mo><mrow><mo>-</mo><mn>1</mn></mrow><mo>;</mo><mn>1</mn><mo stretchy="false">]</mo><mo>,</mo><mspace width="thickmathspace"></mspace><mstyle mathvariant="monospace"><mrow><mo lspace="0em" rspace="thinmathspace">Math.asin</mo><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></mrow></mstyle><mo>=</mo><mo lspace="0em" rspace="0em">arcsin</mo><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo><mo>=</mo><mtext> the unique </mtext><mspace width="thickmathspace"></mspace><mi>y</mi><mo>∊</mo><mrow><mo>[</mo><mrow><mo>-</mo><mfrac><mi>π</mi><mn>2</mn></mfrac><mo>;</mo><mfrac><mi>π</mi><mn>2</mn></mfrac></mrow><mo>]</mo></mrow><mspace width="thinmathspace"></mspace><mtext>such that</mtext><mspace width="thickmathspace"></mspace><mo lspace="0em" rspace="0em">sin</mo><mo stretchy="false">(</mo><mi>y</mi><mo stretchy="false">)</mo><mo>=</mo><mi>x</mi></mrow><annotation encoding="TeX">\forall x \in [{-1};1],\;\mathtt{\operatorname{Math.asin}(x)} = \arcsin(x) = \text{ the unique } \; y \in \left[-\frac{\pi}{2}; \frac{\pi}{2}\right] \, \text{such that} \; \sin(y) = x</annotation></semantics></math></p> -<h2 id="Syntax" name="Syntax">语法</h2> +<h2 id="Syntax">语法</h2> <pre class="syntaxbox">Math.asin(<em>x</em>)</pre> -<h3 id="Parameters" name="Parameters">参数</h3> +<h3 id="Parameters">参数</h3> <dl> <dt> <code>x</code></dt> <dd> 一个数值</dd> </dl> -<h2 id="Description" name="Description">描述</h2> +<h2 id="Description">描述</h2> <p><code>asin</code> 方法接受 -1 到 1 之间的数值作为参数,返回一个介于 <math><semantics><mrow><mo>-</mo><mfrac><mi>π</mi><mn>2</mn></mfrac></mrow><annotation encoding="TeX">-\frac{\pi}{2}</annotation></semantics></math> 到 <math><semantics><mfrac><mi>π</mi><mn>2</mn></mfrac><annotation encoding="TeX">\frac{\pi}{2}</annotation></semantics></math> 弧度的数值。如果接受的参数值超出范围,则返回 <code>NaN</code>。</p> <p>由于 <code>asin</code> 是 <code>Math</code> 的静态方法,所有应该像这样使用:<code>Math.asin()</code>,而不是作为你创建的 <code>Math</code> 实例的方法。</p> -<h2 id="Examples" name="Examples">示例</h2> -<h3 id="Example:_Using_Math.asin" name="Example:_Using_Math.asin">例子:使用 <code>Math.asin()</code></h3> +<h2 id="Examples">示例</h2> +<h3 id="Example:_Using_Math.asin">例子:使用 <code>Math.asin()</code></h3> <pre class="brush:js">Math.asin(-2); // NaN Math.asin(-1); // -1.5707963267948966 (-pi/2) Math.asin(0); // 0 @@ -102,7 +102,7 @@ Math.asin(2); // NaN</pre> </tbody> </table> </div> -<h2 id="See_also" name="See_also">相关链接</h2> +<h2 id="See_also">相关链接</h2> <ul> <li>The {{jsxref("Global_Objects/Math", "Math")}} object it belongs to.</li> <li>{{jsxref("Math.acos()")}}</li> |
