Need help setting up integral. (Doesn't have to be solved)

1. Dec 7, 2009

Ashford

1. The problem statement, all variables and given/known data
Set up a definite integral that could be evaluated to find the volume of the solid that results when the region enclosed by the curves y=(x^2)-1, x=2, and y=0 is revolved about the y-axis.
(doesn't have to be solved) I have look at my book for help and I'm stuck.

2. Dec 7, 2009

ChaoticLlama

What have you tried so far?

Please post your attempt and any rough work that pertains to this problem.

3. Dec 7, 2009

Ashford

I've graphed it, but that still doesn't get me any where I don't know which integral to set it up with.

4. Dec 7, 2009

Ashford

Ok this is what i got probably wrong. V=$$\pi$$ (integral) [x2-1] dy

with the lower limit of the integral being 0 and the top being 2

5. Dec 7, 2009

Staff: Mentor

What does the region that will be revolved around the y axis look like? Have you drawn a sketch of the revolved solid. Are you going to use shells or disks to get the volume?

What expression represents your typical volume element?