```
Plot[(1.8)^n, {n, 0.5, 10}]

```

Works fine, but this derivative gives an error and does not plot.

```
D[(1.8)^n, n] (* also ok *)
Plot[D[(1.8)^n, n], {n, 0.5, 10}, WorkingPrecision -> 300, PlotPoints -> 200]

```

> 
> General::ivar: 0.5000477864321607` is not a valid variable.
> 
> 
> 

> 
> General::ivar: 0.5477864798994975` is not a valid variable.
> 
> 
> 

> 
> General::stop: Further output of General::ivar will be suppressed during this calculation.
> 
> 
> 

How might I be able to change this?
The idea is to be able to plot something like this function and its derivative on the same plot.

```
 Plot[{(1.5)^n, D[(1.5)^n, n]}, {n, -10, 10}, Frame -> True]

```