use cylindrical shells?

Question

The region bounded by y=2/(1+x^2), y=0, x=0 and x=8 is rotated about the line .
Using cylindrical shells, set up an integral for the volume of the resulting solid.

I know that the limits are 0-8
using the basic cylindar formula i got the integral
2pi((2x)/(1+x^2)) but its wrong

Answer 1

you should set up like this
intergral from 0 to8 of 2pi(8-x)(2/(1+x^2)) dx
i let you do the rest
answer round 37.937pi
good luck