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

<AgentInstructions>

## Submitting Feedback

If you encounter incorrect, outdated, or confusing documentation on this page, submit feedback:

POST https://axiom.co/docs/feedback

```json
{
  "path": "/apl/scalar-functions/mathematical-functions/sin",
  "feedback": "Description of the issue"
}
```

Only submit feedback when you have something specific and actionable to report.

</AgentInstructions>

# sin

> This page explains how to use the sin function in APL.

Use the `sin` function in APL to compute the sine of an angle expressed in radians. The function accepts any real number and returns a value in the range \[-1, 1].

`sin` is most commonly used in observability to encode time-of-day or other periodic signals as cyclic coordinates. When combined with `cos`, it produces a two-dimensional representation of periodic phenomena that preserves circular distance. For example, you can encode hour-of-day cyclically so that hour 23 and hour 0 are treated as adjacent.

## For users of other query languages

If you come from other query languages, this section explains how to adjust your existing queries to achieve the same results in APL.

<AccordionGroup>
  <Accordion title="Splunk SPL users">
    In Splunk SPL, `sin()` takes an angle in radians and returns the sine, just like APL.

    <CodeGroup>
      ```sql Splunk example theme={null}
      | eval sin_val = sin(angle_rad)
      ```

      ```kusto APL equivalent theme={null}
      ['sample-http-logs']
      | extend sin_val = sin(angle_rad)
      ```
    </CodeGroup>
  </Accordion>

  <Accordion title="ANSI SQL users">
    In ANSI SQL, `SIN()` is a standard function with identical semantics.

    <CodeGroup>
      ```sql SQL example theme={null}
      SELECT SIN(angle_rad) AS sin_val FROM logs
      ```

      ```kusto APL equivalent theme={null}
      ['sample-http-logs']
      | extend sin_val = sin(angle_rad)
      ```
    </CodeGroup>
  </Accordion>
</AccordionGroup>

## Usage

### Syntax

```kusto theme={null}
sin(x)
```

### Parameters

| Name | Type | Required | Description           |
| ---- | ---- | -------- | --------------------- |
| `x`  | real | Yes      | The angle in radians. |

### Returns

The sine of `x`, a real number in the range \[-1, 1].

## Example

Use `sin` to compute the sine of an angle in radians.

**Query**

```kusto theme={null}
print result = sin(pi() / 2)
```

[Run in Playground](https://play.axiom.co/axiom-play-qf1k/query?initForm=%7B%22apl%22%3A%20%22print%20result%20%3D%20sin%28pi%28%29%20/%202%29%22%7D)

**Output**

| result |
| ------ |
| 1      |

## List of related functions

* [cos](/apl/scalar-functions/mathematical-functions/cos): Returns the cosine. Use `sin` and `cos` together to produce a two-dimensional cyclic encoding of angles.
* [tan](/apl/scalar-functions/mathematical-functions/tan): Returns the tangent. Use it when you need the ratio of sine to cosine.
* [asin](/apl/scalar-functions/mathematical-functions/asin): Returns the arc sine. Use it as the inverse of `sin`.
* [pi](/apl/scalar-functions/mathematical-functions/pi): Returns the constant π. Use it to construct radian values before calling `sin`.
* [radians](/apl/scalar-functions/mathematical-functions/radians): Converts degrees to radians. Use it to prepare degree inputs before calling `sin`.