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Homework Help: Mistake in provided solutions?

  1. Aug 15, 2012 #1
    1. The problem statement, all variables and given/known data

    The problem is attached in the picture.

    3. The attempt at a solution

    If you refer to line 2 of the working, they substituted x with 'b' instead of y with 'b' since the first integral is with respect to y.

    Is this a mistake or is there something more?

    Attached Files:

  2. jcsd
  3. Aug 15, 2012 #2
    Looks to me like they're substituting x=a and x=0 on line 2, just like you'd expect.
  4. Aug 15, 2012 #3


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    The first integral is NOT with respect to y, it is with respect to x.
  5. Aug 15, 2012 #4
    I got a different answer when I integrated with respect to y first... im missing the additional sqrt(b) term..
  6. Aug 15, 2012 #5
    Then you made a mistake somewhere :-)
  7. Aug 16, 2012 #6
    You are right, I saw my mistake.. Thanks btw!
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