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Thread: Please help

  1. #1
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    Please help

    https://imgur.com/gallery/lODhz

    Find the volume of the solid generated by rotating the region about the y axis. I get 2 Pi u^3 but the solution is Pi/2 u^3

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    Re: Please help

    Quote Originally Posted by kpad5991 View Post
    https://imgur.com/gallery/lODhz

    Find the volume of the solid generated by rotating the region about the y axis. I get 2 Pi u^3 but the solution is Pi/2 u^3
    What was the integral you obtained when trying to calculate the volume?

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    Re: Please help

    Quote Originally Posted by InteGrand View Post
    What was the integral you obtained when trying to calculate the volume?
    This is what I got.

    https://imgur.com/gallery/Zvbc3

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    Re: Please help

    Quote Originally Posted by kpad5991 View Post
    You have the correct integral and correct antiderivative. You have just made an error in evaluating



    So you can have another go at evaluating this (carefully). Make sure to get all signs right when evaluating it (you have a sign error in your fourth-from-last line).
    Last edited by InteGrand; 8 Jan 2018 at 7:15 PM.

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    Re: Please help






  6. #6
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    Re: Please help

    Thanks I'm such an idiot silly mistake

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    Re: Please help

    Quote Originally Posted by InteGrand View Post
    You have the correct integral and correct antiderivative. You have just made an error in evaluating



    So you can have another go at evaluating this (carefully). Make sure to get all signs right when evaluating it (you have a sign error in your fourth-from-last line).
    Can you please check where I'm making a mistake for this question below.

    https://imgur.com/gallery/elmgK

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