A question about fourier analysis

1. Aug 16, 2011

rar0308

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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Last edited: Aug 16, 2011
2. Aug 17, 2011

mathfeel

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...

3. Aug 17, 2011

rar0308

Thanks.
It's from page 11 <Quantum Theory> David Bohm, Dover.

4. Aug 17, 2011

daveyp225

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.

5. Aug 18, 2011

pwsnafu

How do you know that l, m, n, l', m', n' are constant?

6. Aug 18, 2011

daveyp225

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.