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Math Help - [SOLVED] How to evaluate this integral

  1. #1
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    Question [SOLVED] How to evaluate this integral

    Hi,
    I would like some help evaluating this indefinite integral

    ∫ [x^2 sqrt(9x+5)] dx

    Im not sure how to go about solving this

    thanks!
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  2. #2
    MHF Contributor red_dog's Avatar
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    \sqrt{9x+5}=u\Rightarrow x=\frac{u^2-5}{9}\Rightarrow dx=\frac{2}{9}udu

    \frac{2}{729}\int(u^2-5)^2u^2du=\frac{2}{729}\int(u^6-10u^4+25u^2)du

    Can you continue?
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  3. #3
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    ahh I understand, thank-you for replying .
    Yes I can continue
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