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Somewhat hard integral

  1. Apr 30, 2012 #1
    1. The problem statement, all variables and given/known data
    [tex]\int e^{3lnx} + e^{3x} dx[/tex]


    2. Relevant equations



    3. The attempt at a solution

    Not sure if I should use an e substitution or if I'm forgetting some easy e rules... Any help appreciated.
     
  2. jcsd
  3. Apr 30, 2012 #2

    Dick

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    You really have two separate problems there. e^(ln(x))=x will help with one of them.
     
  4. Apr 30, 2012 #3
    e^(lnx)=x, do you mean the derivative of e^lnx=x? Why do they give me some stupid rule I don't know -.-"
     
  5. Apr 30, 2012 #4

    Dick

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    No, I mean e^(ln(x))=x. e^x and ln(x) are inverse functions. You didn't know that? Use that to simplify e^(3*ln(x)).
     
  6. Apr 30, 2012 #5
    It's just too much to remember. Thank you though.
     
  7. Apr 30, 2012 #6

    Dick

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    You're welcome. It is pretty basic though. It's sort of the definition of what 'ln(x)' means.
     
  8. Apr 30, 2012 #7
    Yeah I should of thought more, but I kind of instantly thought it was harder than I thought, usually what I do when I see e lol. Plus kind of stressed for this stupid AP exam -.-
     
  9. Apr 30, 2012 #8

    Dick

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    Well, try and destress. That's ones not that hard if you don't panic.
     
  10. Apr 30, 2012 #9
    I know I know :\
     
  11. Apr 30, 2012 #10

    Dick

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    Good luck!
     
  12. Apr 30, 2012 #11
    Thank you..
     
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