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Little help? simple problem

  1. Dec 20, 2007 #1
    hello.. i´m a hs senior in ap calculus bc but i went out of the country for vacations and brough my calculus book with me... i´ve been trying to figure out integration by parts by myself but i stumbled on this problem:confused:
    i know it´s supposed to be simple but it is driving me nuts...

    xlnx dx

    thanks for helping :smile:
  2. jcsd
  3. Dec 20, 2007 #2
    integration by parts, note pick your u and dv carefully
    Last edited: Dec 20, 2007
  4. Dec 20, 2007 #3


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    You have two choices (u=x and dv=lnxdx) or (u=lnx and dv=xdx). Choose the one you think will be easier to handle.
  5. Dec 23, 2007 #4
    Hint, d(ln x)/dx = 1/x....

    Oh, whatever: u = ln x, dv = x => du = 1/x, v = x^2/2.
    So you get (x^2 * ln x)/2 - Int(x/2, x). And you just gotta do that last integral.
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