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Math Help - [SOLVED] volume by cylindrical shell

  1. #1
    Senior Member mollymcf2009's Avatar
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    [SOLVED] volume by cylindrical shell

    I originally posted this in Calculus section and I don't know how to delete it. Can someone do that for me please? I'm getting close to my deadline, so I really need someone to check that I have my integral set up correctly. I can not get the right answer

    Bounding curves:

    y = 8 - x^2 and y = x^2


    Find volume of region bounded by these curves when rotated about x = 2

    I wrote my integral as:

    \int\limits_{-2}^{2}  (2-x)((8-x^2)-(x^2)) dx

    Look okay?
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    Hello, mollymcf2009!

    Bounding curves: . y \:= \:8 - x^2 \,\text{ and }\,y \:=\: x^2
    Find volume of region bounded by these curves when rotated about x = 2.

    I wrote my integral as: . \int_{-2}^2  (2-x)\left[(8-x^2)- x^2\right]\,dx

    Look okay?

    Probably an oversight, but you need {\color{red}2\pi} in front . . . The rest is fine!

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  3. #3
    Senior Member mollymcf2009's Avatar
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    Thank you so much!! Yes, I usually just move the 2\pi out immediately so I forgot to add that.
    Thanks again!!
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    Quote Originally Posted by mollymcf2009 View Post
    I originally posted this in Calculus section and I don't know how to delete it. Can someone do that for me please?
    Done. Next time, please do the following:

    1. Repost the unwanted post using the Report Post tool found top right.
    2. Edit the unwanted post to something like "Please delete, post reported".
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