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Homework Help: Anybody want to check my work?

  1. Aug 1, 2007 #1
    I tried to post this before, but then when I hit post I was forced to see 5 other posts and it doesn't look like my post got put up, but I apologize if it did and I can't find it. Anyways, here we go again:

    This assignment it kind of important, especially as the class is coming to an end. If I could get any of these problems checked I would greatly appreciate it. As you can see I am having some trouble on #3.
    Calc1.jpg
    calc2.jpg
    calc3.jpg
    Thanks.
     
  2. jcsd
  3. Aug 2, 2007 #2

    Gib Z

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    3) Just let ln(x) = u, then du= (1/x) dx and the integral is just [itex]\int u^2 du[/itex]

    7) is correct but set out extremely poorly. (x= infinity - x=1)??

    8) You have the correct reasoning on the second line, the first line is the working for a different question, [itex]\lim_{a\to 0} \int^2_a x^{-3} dx[/itex]

    10) I can see thats incorrect because when you differentiate your result, you get factors of pi that you didn't account for. Check it.
     
  4. Aug 2, 2007 #3

    Dick

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    And in 2) between the third and fourth lines a cos^2(2*phi) magically changes into a cos^2(phi). There should be a 4*phi term in the answer.
     
    Last edited: Aug 2, 2007
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