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Math Help - Double check

  1. #1
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    Exclamation Double check

    Umm for this question:

    If f(x) = x^2(x-3) calculate the area between the X-axis, the lines x=4 and x=6 and the curve y=sqrt(f(x))

    I keep on getting [12(sqrt(3)-1)]/5

    BUT the txtbk answer is [12(4sqrt(3)-1)]/5

    Could someone please check?
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  2. #2
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    Quote Originally Posted by xwrathbringerx View Post
    Umm for this question:

    If f(x) = x^2(x-3) calculate the area between the X-axis, the lines x=4 and x=6 and the curve y=sqrt(f(x))

    I keep on getting [12(sqrt(3)-1)]/5

    BUT the txtbk answer is [12(4sqrt(3)-1)]/5

    Could someone please check?
    I can confirm your setup if you post what you did.
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  3. #3
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    Exclamation

    Sori it's a little messy
    Attached Thumbnails Attached Thumbnails Double check-untitled.jpg  
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  4. #4
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    I'm trying to read through your work, but in the mean time can you tell me how you got the integral A=\int_{4}^{6}x\sqrt{x-3}dx?
    Last edited by Jameson; October 24th 2009 at 11:14 PM.
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  5. #5
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    Ok, so let's just do this the easy way. We need to figure out if you made a wrong calculation or a conceptual error.

    I don't have a calculator on me, so you should evaluate the definite integral you start with from your work and get the decimal answer if you have to. Then convert the two possible answers you have to decimals and see which one is right. If you get the book answer, your work has an error. If you get your answer, then either the book is wrong or you set up the problem wrong.

    This is why I want you to explain your setup.
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