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Math Help - Rotate About the line y = 4

  1. #1
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    Rotate About the line y = 4

    Find the volume of the solid generated by revolving the region bounded by the graphs of the equation about the line y = 4.

    I set y = y to find the boundaries.
    I found the boundaries to x = o
    and x = 3.

    V = pi INT from x = 0 to x = 3 of the function (x)^2 dx.

    My Answer: 9pi.

    Textbook answer: 18pi.

    Where did 18 come from?
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  2. #2
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    Re: Rotate About the line y = 4

    Quote Originally Posted by nycmath View Post
    Find the volume of the solid generated by revolving the region bounded by the graphs of the equation about the line y = 4.
    What graphs? What equations?

    I set y = y to find the boundaries.
    I found the boundaries to x = o
    and x = 3.

    V = pi INT from x = 0 to x = 3 of the function (x)^2 dx.
    I have no idea where you got x^2 because I have no idea what region you are talking about!

    My Answer: 9pi.

    Textbook answer: 18pi.

    Where did 18 come from?
    It is impossible to answer this without knowing what the problem is or what you did.
    Thanks from romsek
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