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Homework Help: Calculus help

  1. Sep 14, 2004 #1
    http://img.photobucket.com/albums/v124/mugenlude99/myhw1.jpg [Broken]

    did i do this correct?

    thanks
     
    Last edited by a moderator: May 1, 2017
  2. jcsd
  3. Sep 14, 2004 #2

    Pyrrhus

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    There's something wrong, you shouldn't do u = e^-x dx, only u = e^-x and when you say -du = e^-x dx, you have to substitute it completely in the integral i mean -\int { tan(u)du}
     
  4. Sep 14, 2004 #3
    i think i know what you're saying, but i took the -1 out since its a constant.

    :confused:
     
  5. Sep 14, 2004 #4

    Pyrrhus

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    that's ok, i'm talking about your substitution... You should not pick u = e^-x dx, why without dx? you will know why not later, and if you have a -du = e^-x dx, you should not have -\int {tanu dx} you should have -\int {tanu du} see what i mean?, remember in your du you have the dx.
     
  6. Sep 14, 2004 #5
    oh sorry yeah that is a careless mistake, but other than the dx it's ok?
     
  7. Sep 15, 2004 #6

    NateTG

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    Aside from that it looks good to me.
     
  8. Sep 15, 2004 #7
    ok thanks a lot guys :)
     
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