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Homework Help: Integration of arctan(u)

  1. Dec 28, 2006 #1
    hi im having trouble integrating arctan(u).

    i have no idea where to even start. i know the derivative of arctan is
    [tex] \frac{1}{x^2+1} [/tex] so i would assume that the integral would be the opposite?
    but i am supposed to prove that [tex] (arctan(u))=u(arctan(u))-\frac{1}{2}ln(1+u^2)+C [/tex]

    i am completely lost please help...any input is much appreciated.
     
  2. jcsd
  3. Dec 28, 2006 #2

    arildno

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    Remember:
    [tex]arctan(u)=1*arctan(u)[/tex]
    :smile:
     
  4. Dec 28, 2006 #3
    so then you are saying that by using integration by parts i should be able to prove this?
     
  5. Dec 28, 2006 #4

    arildno

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    Yep, that does the trick! :smile:
     
  6. Dec 31, 2006 #5

    Gib Z

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    hehe I was thinking that to, love that trick. I need to learn where to use it though, sometimes it leads me off to nowhere..
     
  7. Dec 31, 2006 #6

    arildno

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    But blundering about is a far better thing to do than not dare to commit anything to paper..:smile:
     
  8. Dec 31, 2006 #7

    Gib Z

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    Of Course :D
     
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