# acoth
> Compute the [inverse hyperbolic cotangent][hyperbolic-arctangent] of a number.
## Usage
```javascript
var acoth = require( '@stdlib/math/base/special/acoth' );
```
#### acoth( x )
Computes the [inverse hyperbolic cotangent][hyperbolic-arctangent] of a `number` (in radians).
```javascript
var v = acoth( 2.0 );
// returns ~0.5493
v = acoth( 1.0 );
// returns Infinity
```
The domain of the inverse hyperbolic cotangent is the union of the intervals `(-inf,-1]` and `[1,inf)`. If provided a value on the open interval `(-1,1)`, the function returns `NaN`.
```javascript
var v = acoth( 0.0 );
// returns NaN
v = acoth( 0.5 );
// returns NaN
```
## Examples
```javascript
var linspace = require( '@stdlib/array/linspace' );
var acoth = require( '@stdlib/math/base/special/acoth' );
var x = linspace( 1.0, 5.0, 100 );
var i;
for ( i = 0; i < x.length; i++ ) {
console.log( acoth( x[ i ] ) );
}
```
[hyperbolic-arctangent]: https://en.wikipedia.org/wiki/Inverse_hyperbolic_function