The curves intersects at and , so using cilindrical shel method, the volume is given by .
You may also see the problem like rotating the area between and about the x-axis from to .
intersection values ...
two symmetrical regions in quads I and III
using the method of washers and taking advantage of symmetry ...
Edit: Sorry if I sounded like I was flaming you, that's certainly not my intention. It's just that I know I'm right, factually. Try have an open mind.
2nd Edit: yes, pony, you're right, that's the right answer.