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title: atan
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description: MuleSoft Documentation Site
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---
---
product: DataWeave
version: 2.13
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---

# atan

> For the full documentation index, see: https://docs.mulesoft.com/llms.txt

## atan(angle: Number): Number

Returns an arc tangent value that can range from `-pi/2` through `pi/2`.

_Introduced in DataWeave version 2.4.0._

### Parameters

<table><colgroup><col> <col></colgroup><thead><tr><th>Name</th><th>Description</th></tr></thead><tbody><tr><td><p><code>angle</code></p></td><td><div><div><p>Number to convert into its arc tangent value.</p></div></div></td></tr></tbody></table>

### Example

This example shows how `atan` behaves with different inputs.

#### Source

```DataWeave
%dw 2.0
import * from dw::util::Math
output application/json
---
{
  "atan0":  atan(0),
  "atan13": atan(0.13),
  "atan-1": atan(-1)
}
```

#### Output

```Json
{
   "atan0": 0.0,
   "atan13": 0.12927500404814307,
   "atan-1": -0.7853981633974483
}
```