`Math.asinh()` 函数返回给定数字的反双曲正弦值, 即：

Math.asinh(x)=arsinh(x)= 特定的 y 满足 sinh(y)=x\mathtt{\operatorname{Math.asinh}(x)} = \operatorname{arsinh}(x) = \text{ the unique } \; y \; \text{such that} \; \sinh(y) = x

## 语法

    Math.asinh(x)

### 参数

`x`
  待计算的数字。

### 返回值

给定数值的反双曲正弦值。

## 描述

`由于asinh()是` `Math的静态方法`, `用户应该直接通过Math.asinh()来使用`, 而不是先创建出Math对象再调用该方法（`Math`不是一个构造器）。

## 示例

### `使用Math.asinh()`

    Math.asinh(1);  // 0.881373587019543
    Math.asinh(0);  // 0

## 其他实现方式

由于arsinh(x)=ln(x+x 2+1)\operatorname {arsinh} (x) = \ln \left(x + \sqrt{x^{2} + 1} \right) ，因此该函数可以被如下的函数所模拟：

    Math.asinh = Math.asinh || function(x) {
      if (x === -Infinity) {
        return x;
      } else {
        return Math.log(x + Math.sqrt(x * x + 1));
      }
    };

## 规范

Specification | Status | Comment
--- | --- | ---
ECMAScript 2015 (6th Edition, ECMA-262) Math.asinh | Standard | Initial definition.
ECMAScript Latest Draft (ECMA-262) Math.asinh | Draft |

## 浏览器兼容性

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

- Desktop
- Mobile

Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari
--- | --- | --- | --- | --- | ---
Basic support | 38 | 25 (25) | 未实现 | 25 | 7.1

Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile
--- | --- | --- | --- | --- | --- | ---
Basic support | 未实现 | 未实现 | 25.0 (25) | 未实现 | 未实现 | 8

## 另见

- `Math.acosh()`
- `Math.atanh()`
- `Math.cosh()`
- `Math.sinh()`
- `Math.tanh()`