> ## Documentation Index
> Fetch the complete documentation index at: https://docs.firebolt.io/llms.txt
> Use this file to discover all available pages before exploring further.

> Reference material for ACOS function

# ACOS

Calculates the arccosine of a value in radians.

## Syntax

```sql theme={"theme":{"light":"css-variables","dark":"css-variables"}}
ACOS(<value>)
```

## Parameters

| Parameter | Description                                           | Supported input types |
| :-------- | :---------------------------------------------------- | :-------------------- |
| `<value>` | The number that the arccosine function is applied to. | `DOUBLE PRECISION`    |

## Return Type

`ACOS` returns a value of type `DOUBLE PRECISION`.

## Example

The following query calculates the arccosine of 1:

<div className="query-window">
  ```
  SELECT ACOS(1) as result;
  ```

  | result <span>double</span> |
  | :------------------------- |
  | 0                          |

  <p><span>Rows: 1</span><span>Execution time: 5.47ms</span></p>
</div>