### Why does this not integrate

why is this integral performed:

```
forget()
var('n')
assume(n>0)
integrate(1/sqrt(1+x^2*n),x,1,2)
```

i.e. I get:

```
-arcsinh(sqrt(n))/sqrt(n) + arcsinh(2*sqrt(n))/sqrt(n)
```

while this is not

```
forget()
var('n')
assume(n>0)
integrate(1/sqrt(1+x^2/n),x,1,2)
```