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Homework Help: What is going on?

  1. Apr 14, 2007 #1
    Take int(F*(x-y/2)F(x-y/2))dy over all y. Where F is a complex function

    Let A=x-y/2

    dA/dy=-1/2 => dy=-2dA

    So -2int(F*(A)F(A))dA = int(F*(x-y/2)F(x-y/2))dy

    but int(F*(A)F(A))dA >0 so is int(F*(x-y/2)F(x-y/2))dy but from the result it looks as if int(F*(x-y/2)F(x-y/2))dy<0

    What is going on?
  2. jcsd
  3. Apr 14, 2007 #2
    Isn't there a -2 somewhere in the new integral?
  4. Apr 14, 2007 #3


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    Science Advisor

    What happened to your limits of integration? Replacing a function of y by a function of A will "reverse" the limits of integration.
  5. Apr 14, 2007 #4
    Right. Good one.
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