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

  1. Dec 7, 2009 #1
    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. jcsd
  3. Dec 7, 2009 #2
    What have you tried so far?

    Please post your attempt and any rough work that pertains to this problem.
  4. Dec 7, 2009 #3
    I've graphed it, but that still doesn't get me any where I don't know which integral to set it up with.
  5. Dec 7, 2009 #4
    Ok this is what i got probably wrong. V=[tex]\pi[/tex] (integral) [x2-1] dy

    with the lower limit of the integral being 0 and the top being 2
  6. Dec 7, 2009 #5


    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?
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