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Homework Help: Integrate from 0 to b

  1. Jun 23, 2008 #1
    1. The problem statement, all variables and given/known data
    i do not know where to start with this one can anyone point me where to go please?

    [tex]\int \frac{1}{x^{4}+1}[/tex]

    lower limit = 0 upper = infinity

    2. Relevant equations

    like i said i dont know where to go with this one.
    i mean i know im going to have to do integrate from 0 to b but i dont know where to start here.
    3. The attempt at a solution
  2. jcsd
  3. Jun 23, 2008 #2
    It seems really messy if you integrate using substitutions ... etc.

    I would recommend using f = 1/(x^2.y^2+1)

    some matlab mess

    >> f = 1/(x^4+1)

    f =


    >> int(f,x,0,inf)

    ans =


    >> int(f,x)

    ans =

  4. Jun 23, 2008 #3
    o wait i think i need to compare i think i have it ill repost. thanks rootX seeing your answer made me see that we have yet to really learn that, so it cant be. thanks again. ill post with what i get to see if im right.
  5. Jun 23, 2008 #4


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    Homework Helper

    Here some hints to get you going. You'll have to decompose it to partial fractions, complete a square, and then use the derivative for arctan f(x). It's quite tedious, but most certainly doable.
  6. Jun 24, 2008 #5
    Re: integrate

    http://www.4nw.net/get-6-2008-6x9cp3w5.JPG[/URL] [Broken]
    http://www.4nw.net/get-6-2008-syhlk7fm.JPG[/URL] [Broken]
    Last edited by a moderator: May 3, 2017
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