> For the complete documentation index, see [llms.txt](https://docs.cascade.io/cascade/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cascade.io/cascade/functions-and-expressions/functions/math/acos.md).

# ACOS

ACOS(`number`, `radians`)

Returns the arc cosine of a `number`. Default produces result in radians.

### Arguments <a href="#arguments" id="arguments"></a>

| Argument  | Description                                                                      |
| --------- | -------------------------------------------------------------------------------- |
| `number`  | Number to take arc cosine of.                                                    |
| `radians` | True to produce output in radians (default), false to produce output in degrees. |

### Output <a href="#output" id="output"></a>

The arc cosine of a `number`.

### Example <a href="#examples" id="examples"></a>

{% embed url="<https://datawrapper.dwcdn.net/l1I2I/2/>" %}