# ATANH

> Calculate the hyperbolic arc tangent (inverse hyperbolic tangent) of a number, returning an angle in radians using SQL in StackQL.

Source: https://stackql.io/language-spec/functions/math/trigonometric/atanh

Calculates the hyperbolic arc tangent (inverse hyperbolic tangent) of a number, which is the value \( \theta \) in radians whose hyperbolic tangent is the specified number.

See also:  
[[`SELECT`]](/language-spec/select)

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## Syntax

```sql
SELECT ATANH(value) FROM <multipartIdentifier>;
```

## Arguments

__*value*__  
A numeric expression within the range of -1 to 1 (exclusive), for which the hyperbolic arc tangent is to be calculated.

## Return Value(s)
Returns the hyperbolic arc tangent of the specified value in radians.

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## Examples

### Calculate the hyperbolic arc tangent of 0.5

```sql
SELECT ATANH(0.5) AS hyperbolic_arc_tangent_value;
```

This query returns approximately `0.5493`, as the hyperbolic arc tangent of 0.5 is about 0.5493 radians.

### Calculate the hyperbolic arc tangent of -0.5

```sql
SELECT ATANH(-0.5) AS hyperbolic_arc_tangent_value;
```

This query calculates the hyperbolic arc tangent of -0.5, resulting in approximately `-0.5493`, as this is the value in radians whose hyperbolic tangent is -0.5.