ATAN function - Amazon Redshift
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# ATAN function

ATAN is a trigonometric function that returns the arc tangent of a number. The return value is in radians and is between `-PI` and `PI`.

## Syntax

``ATAN(number)``

## Arguments

number

The input parameter is a `DOUBLE PRECISION` number.

## Return type

`DOUBLE PRECISION`

## Examples

To return the arc tangent of `1` and multiply it by 4, use the following example.

``````SELECT ATAN(1) * 4 AS pi;

+-------------------+
|        pi         |
+-------------------+
| 3.141592653589793 |
+-------------------+``````

To convert the arc tangent of `1` to the equivalent number of degrees, use the following example.

``````SELECT (ATAN(1) * 180/(SELECT PI())) AS degrees;

+---------+
| degrees |
+---------+
|      45 |
+---------+``````