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Math Help - Verification on a x-axis rotation

  1. #1
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    Verification on a x-axis rotation

    The problem is as follows

    "Consider the solid obtained by rotating the region bounded by the given curves about the x-axis.

    y=5/x, x=8, x=16, y=0

    Find the volume V of this solid."

    For a solution I get

    pi(5ln(16)-5ln(8))

    Is this correct? I am asking because i've done the problem multiple times and am submitting it electronically for homework but it won't accept it or any other simplified form.

    Thanks in advance.
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  2. #2
    MHF Contributor
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    It looks like you did \int_{8}^{16} \pi \frac{5}{x}dx, but the formula that you should use is V=\int_{a}^{b} \pi [f(x)]^2dx.
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