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A question about fourier analysis

  1. Aug 16, 2011 #1
    Hi.
    see the image.
    In the integral there's no dx,dy,dz thing. Does this make any sense?
    Isn't it errata?
     

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  2. jcsd
  3. Aug 17, 2011 #2
    It is wrong without the dx, dy, dz thing. If this comes from some hand written note, it's usually implied. If this comes from a book, you need to kick the editor in the nut...
     
  4. Aug 17, 2011 #3
    Thanks.
    It's from page 11 <Quantum Theory> David Bohm, Dover.
     
  5. Aug 17, 2011 #4
    It makes sense if the order does not matter for integration. If it is obvious in context that the variables here are x,y,z (L is clearly a constant as integrals contain it) and Fubini's Theorem is satisfied then you are free to choose.
     
  6. Aug 18, 2011 #5

    pwsnafu

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    How do you know that l, m, n, l', m', n' are constant?
     
  7. Aug 18, 2011 #6
    I said "if it was obvious in context the variables are x, y and z". Otherwise, call it a good hunch, as there are only three integration variables present and the ' notation often signifies a relationship between, for example, m and m'. All six cannot be integration variables, and if the first three were then the second sine function is only a constant with respect to integration and would probably not be part of the integrand.
     
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