Volume of an object obtained by rotating a region bounded by functions

Question

The region bounded by $xy=1$ and $x=1, x=3, y=0$, rotated about $x=-1$.

I figured out the fact that I have to use Cylindrical Shell method, since

$$\int A_{outer} - A_{inner}$$ thing doesn't work in this case.

I'm still not sure how to use the Cylindrical Shell method. Can I just get the explanation of how to use the Cylindrical Shell method?

Answer 1

$V=2\pi\int_1^3(x+1)\frac1x\,dx$