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DFT/QFT help

  1. Dec 16, 2004 #1
    Please see the attachment

    Can anyone tell me why the bracketed term = 0 if c does not equal and integer multiple of q/r ...

    Thanks :(

    Attached Files:

  2. jcsd
  3. Dec 16, 2004 #2
    Think of it as an integral over a sine or cosine function. If it is not an integral number of periods, then the integral(sum) averages to zero.
  4. Dec 19, 2004 #3

    can you provide some more indept info ??? Were there any boundary-conditions given ???

    I can't really find any solution to your problem based upon these data???

    Can you post the entire display of this formula and how it is constructed???

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