---
title: math.acosh() function
description: >
  `math.acosh()` returns the inverse hyperbolic cosine of `x`.
menu:
  flux_v0_ref:
    name: math.acosh
    parent: math
    identifier: math/acosh
weight: 101
---

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`math.acosh()` returns the inverse hyperbolic cosine of `x`.



##### Function type signature

```js
(x: float) => float
```

{{% caption %}}
For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
{{% /caption %}}

## Parameters

### x
({{< req >}})
Value to operate on.

`x` should be greater than 1. If less than 1 the operation will return `NaN`.


## Examples

- [Return the inverse hyperbolic cosine of a value](#return-the-inverse-hyperbolic-cosine-of-a-value)
- [Use math.acosh in map](#use-mathacosh-in-map)

### Return the inverse hyperbolic cosine of a value

```js
import "math"

math.acosh(x: 1.22)

```


### Use math.acosh in map

```js
import "math"

data
    |> map(fn: (r) => ({r with _value: math.acosh(x: r._value)}))

```

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{{% expand "View example input and output" %}}

#### Input data

| _time                | *tag | _value               |
| -------------------- | ---- | -------------------- |
| 2021-01-01T00:00:00Z | t1   | -0.21800000000000003 |
| 2021-01-01T00:00:10Z | t1   | 1.092                |
| 2021-01-01T00:00:20Z | t1   | 0.735                |
| 2021-01-01T00:00:30Z | t1   | 1.7530000000000001   |
| 2021-01-01T00:00:40Z | t1   | 1.5230000000000001   |
| 2021-01-01T00:00:50Z | t1   | 0.443                |

| _time                | *tag | _value              |
| -------------------- | ---- | ------------------- |
| 2021-01-01T00:00:00Z | t2   | 1.9850000000000003  |
| 2021-01-01T00:00:10Z | t2   | 0.497               |
| 2021-01-01T00:00:20Z | t2   | -0.375              |
| 2021-01-01T00:00:30Z | t2   | 1.977               |
| 2021-01-01T00:00:40Z | t2   | 1.3860000000000001  |
| 2021-01-01T00:00:50Z | t2   | 0.18600000000000003 |


#### Output data

| _time                | _value              | *tag |
| -------------------- | ------------------- | ---- |
| 2021-01-01T00:00:00Z | NaN                 | t1   |
| 2021-01-01T00:00:10Z | 0.42572984537574377 | t1   |
| 2021-01-01T00:00:20Z | NaN                 | t1   |
| 2021-01-01T00:00:30Z | 1.1608966388962805  | t1   |
| 2021-01-01T00:00:40Z | 0.9827177940622978  | t1   |
| 2021-01-01T00:00:50Z | NaN                 | t1   |

| _time                | _value             | *tag |
| -------------------- | ------------------ | ---- |
| 2021-01-01T00:00:00Z | 1.308254013849232  | t2   |
| 2021-01-01T00:00:10Z | NaN                | t2   |
| 2021-01-01T00:00:20Z | NaN                | t2   |
| 2021-01-01T00:00:30Z | 1.3035758471451702 | t2   |
| 2021-01-01T00:00:40Z | 0.8525776257667146 | t2   |
| 2021-01-01T00:00:50Z | NaN                | t2   |

{{% /expand %}}
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