I was trying to understand the proof given in this wiki page:(adsbygoogle = window.adsbygoogle || []).push({});

http://en.wikipedia.org/wiki/Dirichlet_integral

But I'm sure their proof is correct because I don't know if the step where he says the sine is the imaginary part of the the exponential and then expands it to the whole of the integral is correct.

[tex]\int_0^{\infty} e^{-\alpha \omega} Im( e^{i \beta \omega}) = Im( \int_0^{\infty} e^{-\alpha \omega} e^{i \beta \omega})[/tex]

I doesn't make much sense to me. That whole part of the demonstration is very unclear to me.

Anyone know this?

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# Dirichlet integral

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