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Math.SQRT1_2

Math.SQRT1_2

Math.SQRT1_2属性表示 1/2 的平方根,约为 0.707:

Math.SQRT1_2=12=12≈0.707\mathtt{\mi{Math.SQRT1_2}} = \sqrt{\frac{1}{2}} = \frac{1}{\sqrt{2}} \approx 0.707

| Math.SQRT1_2属性的属性特性 |

|:----|

| Writable | no |

| Enumerable | no |

| Configurable | no |

描述

由于SQRT1_2Math 对象的静态属性,所以应该像这样使用:Math.SQRT1_2,而不是作为你创建的 Math 实例的属性(Math不是构造函数)。

示例

使用Math.SQRT1_2

下面的函数返回 1/2 的平方根:

function getRoot1_2() { return Math.SQRT1_2; } getRoot1_2( // 0.7071067811865476

规范

SpecificationStatusComment
ECMAScript 1st Edition (ECMA-262)StandardInitial definition. Implemented in JavaScript 1.0.
ECMAScript 5.1 (ECMA-262)The definition of 'Math.SQRT1_2' in that specification.Standard
ECMAScript 2015 (6th Edition, ECMA-262)The definition of 'Math.SQRT1_2' in that specification.Standard
ECMAScript Latest Draft (ECMA-262)The definition of 'Math.SQRT1_2' in that specification.Draft

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