## COSH

The `COSH` function in ES|QL returns the hyperbolic cosine of an angle. The angle should be provided in radians. If the provided angle is null, the function will return null.

### Examples

Here are a couple of examples of how you can use the `COSH` function in ES|QL:

```esql
ROW a=1.8
| EVAL cosh = COSH(a)
```

In this example, the `COSH` function is used to calculate the hyperbolic cosine of the angle `1.8` radians.

```esql
ROW a=0
| EVAL cosh = COSH(a)
```

In this second example, the `COSH` function is used to calculate the hyperbolic cosine of the angle `0` radians.