Why is it that the Fourier transform of [tex] e^{2\pi ikx} [/tex] is equal to [tex] \delta(k) [/tex] ? The delta function is supposed to be zero except at one point. But the integral doesn't converge for [tex] k \ne 0 [/tex]. Yet I see a lot of books on QFT use this identity.(adsbygoogle = window.adsbygoogle || []).push({});

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# Why is Fourier transform of exp(ix) a delta?

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