# ACOSH

**The ACOSH function returns the hyperbolic arccosine of a number.**

This function takes a single [Number](../../variable-data-types/the-number-variable-data-type) as input. It outputs that Number's inverse hyperbolic cosine.

#### Declaration

```javascript
ACOSH(number) -> hyperbolic_arccosine
```

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#### Parameters

**number** (required, type: _Number_) The number to calculate the hyperbolic arccosine for.

#### Return Values

**hyperbolic\_arccosine** (type: _Number_) The hyperbolic arccosine of the given number.

#### Examples

The following example returns the hyperbolic arccosine of 1:

```javascript
ACOSH(1) -> 0
```
