# acos(n)

Returns the arccosine value of radians value *n*. *n* can be any real numeric value in the range of -1 <= *n* <= 1. If `null` is passed as an argument, `acos()` returns `null`. This function can only be used in a `foreach` statement.

## Example

```nolang
q = foreach q generate acos(radians) as arccosine;
```