Math.atanh() function returns the hyperbolic arctangent of a number, that is

x ( - 1 , 1 ) , Math.atanh ( x ) = arctanh ( x ) = the unique y such that tanh ( y ) = x \forall x \in \left( -1, 1 \right), \mathtt{\operatorname{Math.atanh}(x)} = \operatorname{arctanh}(x) = \text{ the unique } \; y \; \text{such that} \; \tanh(y) = x

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句法

Math.atanh(x)
					

参数

x

A number.

返回值

The hyperbolic arctangent of the given number.

描述

因为 atanh() is a static method of Math , you always use it as Math.atanh() , rather than as a method of a Math object you created ( Math is not a constructor).

Polyfill

For | x | < 1 \left|x\right| < 1 , we have artanh ( x ) = 1 2 ln ( 1 + x 1 - x ) \operatorname {artanh} (x) = \frac{1}{2}\ln \left( \frac{1 + x}{1 - x} \right) so this can be emulated by the following function:

Math.atanh = Math.atanh || function(x) {
  return Math.log((1+x)/(1-x)) / 2;
};
					

范例

使用 Math.atanh()

Math.atanh(-2);  // NaN
Math.atanh(-1);  // -Infinity
Math.atanh(0);   // 0
Math.atanh(0.5); // 0.5493061443340548
Math.atanh(1);   // Infinity
Math.atanh(2);   // NaN
					

For values greater than 1 or less than -1, NaN 被返回。

规范

规范
ECMAScript (ECMA-262)
The definition of 'Math.atanh' in that specification.

浏览器兼容性

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图例

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完整支持

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另请参阅

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