My teacher worked out the following and said it's a unitary transformation (how?) of exp(ikx). He said we're supposed to find the periodic bounds of integration - but I thought for Fourier transforms the bounds are negative infinity to infinity, so in this case shouldn't it just be the Dirac delta function? Also, how do you get the 2 in front of the sin? When I rewrite using Euler's identity, there is no 2.(adsbygoogle = window.adsbygoogle || []).push({});

[tex]

\int e^{ik(x-x')}dk=\frac{e^{ik(x-x')}}{i(x-x')}\approx \frac{2sin[k(x-x')]}{x-x'}

[/tex]

He then substituted x' with the deBroglie wave length at the Fermi level. I'm not sure what the physical meaning is...

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# Homework Help: Fourier transforms

Can you offer guidance or do you also need help?

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