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

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`math.atanh()` returns the inverse hyperbolic tangent 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 and less than 1. Otherwise the operation
will return `NaN`.


## Examples

- [Return the hyperbolic tangent of a value](#return-the-hyperbolic-tangent-of-a-value)
- [Use math.atanh in map](#use-mathatanh-in-map)

### Return the hyperbolic tangent of a value

```js
import "math"

math.atanh(x: 0.22)// 0.22365610902183242


```


### Use math.atanh in map

```js
import "math"

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

```

{{< expand-wrapper >}}
{{% expand "View example input and output" %}}

#### Input data

| _time                | *tag | _value                |
| -------------------- | ---- | --------------------- |
| 2021-01-01T00:00:00Z | t1   | -0.021800000000000003 |
| 2021-01-01T00:00:10Z | t1   | 0.1092                |
| 2021-01-01T00:00:20Z | t1   | 0.0735                |
| 2021-01-01T00:00:30Z | t1   | 0.1753                |
| 2021-01-01T00:00:40Z | t1   | 0.15230000000000002   |
| 2021-01-01T00:00:50Z | t1   | 0.0443                |

| _time                | *tag | _value               |
| -------------------- | ---- | -------------------- |
| 2021-01-01T00:00:00Z | t2   | 0.1985               |
| 2021-01-01T00:00:10Z | t2   | 0.0497               |
| 2021-01-01T00:00:20Z | t2   | -0.0375              |
| 2021-01-01T00:00:30Z | t2   | 0.1977               |
| 2021-01-01T00:00:40Z | t2   | 0.1386               |
| 2021-01-01T00:00:50Z | t2   | 0.018600000000000002 |


#### Output data

| _time                | _value                | *tag |
| -------------------- | --------------------- | ---- |
| 2021-01-01T00:00:00Z | -0.021803454395720394 | t1   |
| 2021-01-01T00:00:10Z | 0.10963718917920522   | t1   |
| 2021-01-01T00:00:20Z | 0.07363278579671062   | t1   |
| 2021-01-01T00:00:30Z | 0.17712951464974935   | t1   |
| 2021-01-01T00:00:40Z | 0.1534942122028045    | t1   |
| 2021-01-01T00:00:50Z | 0.04432901360668446   | t1   |

| _time                | _value                | *tag |
| -------------------- | --------------------- | ---- |
| 2021-01-01T00:00:00Z | 0.2011705409124157    | t2   |
| 2021-01-01T00:00:10Z | 0.049740981912241244  | t2   |
| 2021-01-01T00:00:20Z | -0.037517592971457035 | t2   |
| 2021-01-01T00:00:30Z | 0.20033786359692538   | t2   |
| 2021-01-01T00:00:40Z | 0.13949787194848565   | t2   |
| 2021-01-01T00:00:50Z | 0.01860214539735061   | t2   |

{{% /expand %}}
{{< /expand-wrapper >}}