From 33058f2b292b3a581333bdfb21b8f671898c5060 Mon Sep 17 00:00:00 2001 From: Peter Bengtsson Date: Tue, 8 Dec 2020 14:40:17 -0500 Subject: initial commit --- .../reference/global_objects/math/sqrt/index.html | 81 ++++++++++++++++++++++ 1 file changed, 81 insertions(+) create mode 100644 files/zh-cn/web/javascript/reference/global_objects/math/sqrt/index.html (limited to 'files/zh-cn/web/javascript/reference/global_objects/math/sqrt') diff --git a/files/zh-cn/web/javascript/reference/global_objects/math/sqrt/index.html b/files/zh-cn/web/javascript/reference/global_objects/math/sqrt/index.html new file mode 100644 index 0000000000..badb08802a --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/math/sqrt/index.html @@ -0,0 +1,81 @@ +--- +title: Math.sqrt() +slug: Web/JavaScript/Reference/Global_Objects/Math/sqrt +translation_of: Web/JavaScript/Reference/Global_Objects/Math/sqrt +--- +
{{JSRef}}
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Math.sqrt() 函数返回一个数的平方根,即:

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x0,Math.sqrt(x)=x=the uniquey0such thaty2=x\forall x \geq 0, \mathtt{Math.sqrt(x)} = \sqrt{x} = \text{the unique} \; y \geq 0 \; \text{such that} \; y^2 = x

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{{EmbedInteractiveExample("pages/js/math-sqrt.html")}}

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语法

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Math.sqrt(x) 
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参数

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x
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一个数值
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描述

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如果参数 number 为负值,则 sqrt 返回{{jsxref("NaN")}}。

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由于 sqrt 是 Math 的静态方法,所以应该像这样使用:Math.sqrt(),而不是作为你创建的 Math 实例的方法。

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示例

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使用 Math.sqrt

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Math.sqrt(9); // 3
+Math.sqrt(2); // 1.414213562373095
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+Math.sqrt(1);  // 1
+Math.sqrt(0);  // 0
+Math.sqrt(-1); // NaN
+Math.sqrt(-0); // -0
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规范

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规范版本规范状态注解
ECMAScript 1st Edition. Implemented in JavaScript 1.0StandardInitial definition.
{{SpecName('ES5.1', '#sec-15.8.2.17', 'Math.sqrt')}}{{Spec2('ES5.1')}}
{{SpecName('ES6', '#sec-math.sqrt', 'Math.sqrt')}}{{Spec2('ES6')}}
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浏览器兼容性

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{{Compat("javascript.builtins.Math.sqrt")}}

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参见

+ + -- cgit v1.2.3-54-g00ecf