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Math Help - I do not understand or get these problems?

  1. #1
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    I do not understand or get these problems?



    Yeah.. Homework help. I seriously do not understand it even though I am following exact procedures and made sure I wasn't wrong, but I'm still wrong? I'm on my last submission for my online homework in order to get points and I would like to get it right.. But I don't understand it?
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  2. #2
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    Quote Originally Posted by elpermic View Post


    Yeah.. Homework help. I seriously do not understand it even though I am following exact procedures and made sure I wasn't wrong, but I'm still wrong? I'm on my last submission for my online homework in order to get points and I would like to get it right.. But I don't understand it?
    Please show all your working so that you can be pointed in the right direction.
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  3. #3
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    well for the 1st one..

    i take the integral of π r^2 from [0,2] and I get 8.378 as my answer(im sure this is right.. but im wrong)

    as for the 2nd one

    i take the integral of 4(3-3x^2) from [-1,1] and after calculation i get 24. still wrong though
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  4. #4
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    Quote Originally Posted by elpermic View Post
    well for the 1st one..

    i take the integral of π r^2 from [0,2] and I get 8.378 as my answer(im sure this is right.. but im wrong)

    as for the 2nd one

    i take the integral of 4(3-3x^2) from [-1,1] and after calculation i get 24. still wrong though
    I will point you in the right direction for #1:

    \displaystyle V = \pi \int_3^5 x^2 \, dy. An exact answer is probably required.
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  5. #5
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    Sorry. I forgot to say I tried that integral as well and I got 98π/3.. But my answer was still wrong.
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  6. #6
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    Quote Originally Posted by elpermic View Post
    Sorry. I forgot to say I tried that integral as well and I got 98π/3.. But my answer was still wrong.
    In my first reply I bold faced the word "all" for a very good reason. Show all your work, every step.
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  7. #7
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    those were the only 2 integrals I tried. Both of them are wrong and Im still confused because I'm sure I did everything right.
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  8. #8
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    I finally got the answer to the first problem! But I still can't do the second one.
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  9. #9
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    Quote Originally Posted by elpermic View Post
    I finally got the answer to the first problem! But I still can't do the second one.
    I will point you in the right direction: \displaystyle V = \int_0^3 (2x)^2 \, dy.

    Your job is to understand where this has come from and what to do with it.
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