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Homework Help: Integrate by parts twice help

  1. Feb 6, 2004 #1
    I am studying for a midterm, was browsing over an old midterm and found this question


    [tex]
    \int e^{3x} \cos{(x)}\; dx
    [/tex]

    Can't figure it out, help would be appreciated
     
  2. jcsd
  3. Feb 6, 2004 #2

    jamesrc

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    Integrate by parts twice. Post back if you get stuck.
     
  4. Feb 6, 2004 #3
    erm didn't think we'd gotten that far, assignment on that section isnt due until monday. No wonder I couldn't find it hehe.

    O well I have 2 hrs to learn it I'm good! :)
     
  5. Feb 6, 2004 #4
    hmm I ended up with

    [tex]
    \int e^{3x} \cos{(x)}\; dx = \frac{e^{3x}\sin{(x)} + 3e^{3x} \cos{(x})} {10}
    [/tex]

    that sound about right?
     
  6. Feb 6, 2004 #5

    jamesrc

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    Looks good to me.
     
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