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Homework Help: Problem in transition from phasor to normal

  1. Feb 11, 2010 #1
    2mrf6f6.jpg

    oiler formula says
    cosx+isinx

    but here they multiply by minus the imaginary part of the phasor representation
    the coefficient of sine is minus the imaginary part
    why??
     
  2. jcsd
  3. Feb 11, 2010 #2

    LCKurtz

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    That's "Euler" formula. A Frenchman, not a oil tanker. And I suppose you mean the identity

    [tex]e^{ix} = \cos x + i\sin x[/tex]

    I have no idea what your image has to do with your question. Do you mean this? :

    [tex]e^{-ix} = \cos{(- x)} + i\sin {(-x)} = \cos x - i\sin x[/tex]
     
  4. Feb 12, 2010 #3

    CEL

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    A nitpick: Euler was Swiss, not French.
     
  5. Feb 12, 2010 #4

    LCKurtz

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    You are right! And I see upon looking him up, I would also have misspelled his first name had I mentioned it. :redface:
     
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