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Homework Help: Taking imaginary integral and derivative

  1. Nov 17, 2012 #1
    1. The problem statement, all variables and given/known data

    when im solving quantum problem, i see an equation like e^(-kx) e^(icx) i is imaginary. how can i take the integral and derivative of this function

    2. Relevant equations

    e^ix ) cosx + isinx

    3. The attempt at a solution

    actually i tried e^x(-k+ic) and i said the derivative is just (-k+ic)* e^x(-k+ic) :)

    please help and teach me!
     
  2. jcsd
  3. Nov 17, 2012 #2
    What you did is correct. You can treat complex constants as if they were real in differentiation and integration. However, I would recommend getting some introductory text on complex analysis and study it at least until differentiation and integration are introduced.
     
  4. Nov 17, 2012 #3
  5. Nov 17, 2012 #4
    That's because it is confused by the input. Note it treats "icx" as all caps CIX and assumes it is a constant.
     
  6. Nov 17, 2012 #5
    agh :) thank you very much i understand now :)
     
  7. Nov 17, 2012 #6

    haruspex

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    Wolfram seems to have treated the second x as some constant X. In fact, it looks suspiciously as though it has interpreted "icx" as Roman Numerals "CIX" (109). Bizarre.
     
  8. Nov 17, 2012 #7
    yes it is very confusing im trying to find solution for 2 hours just because of that it is funny it takes my precious time :)
     
  9. Nov 17, 2012 #8
    A space after i and before c does wonders. But the output is still a bit odd.
     
  10. Nov 17, 2012 #9

    SammyS

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    Yes, [itex]\ \ i(c+i k) e^{-k x+i c x}\ \ [/itex] is a bit odd, isn't it?
     
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