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Volume of revolution, where am i going wrong?

  1. Jul 7, 2013 #1
    1. The problem statement, all variables and given/known data
    Find the volume of solid obtained by rotating the region bounded by y=x^2,y=4 and x=0 about the line x=-2 using the shell method.

    2. Relevant equations
    I'm stuck because using disks I got the right answer 136pi/3 but I cant using shells?


    3. The attempt at a solution
    Integral 2pi (2+x) (4-x^2) dx from x=0 to 2. This gives 88 pi/3..

    Please help!
     
  2. jcsd
  3. Jul 7, 2013 #2

    LCKurtz

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    Why do you think ##136\pi/3## is correct? Your ##88\pi/3## looks correct to me. Hard to say what mistake you make, not seeing your work.
     
  4. Jul 7, 2013 #3
    I agree, the correct answer is 88/3 *pi
     
  5. Jul 7, 2013 #4

    LCKurtz

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  6. Jul 7, 2013 #5

    Redbelly98

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