Fourier transform limit of finite signal

AI Thread Summary
The discussion revolves around proving that the Fourier Transform of a finite energy signal approaches zero as the frequency approaches infinity. The user is uncertain about how to begin the proof, considering using Parseval's theorem or the integral form of the Fourier Transform. They express frustration over the simplicity of the solution, indicating that they are preparing for an Electronics Math exam. The key point is the relationship between finite energy signals and their Fourier Transforms, which implies that the transform must diminish at high frequencies. The conversation highlights the challenge of applying theoretical concepts to practical problems in signal processing.
omaciu
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So this is a very simple question that I am having some trouble figuring out:

Let s(t) be a finite energy signal with Fourier Transform S(w).
Show that \lim_{w \to \infty } S(w) = 0

We know by defintion that the FT of this signal is \ints(t)e^{-jwt}dt and also that ∫|s(t)|2dt < ∞.

I'm a little lost on how I can start proving this. I thought about something using Parseval's theorem but I have no idea. Or maybe I can use the FT in it's ∫s(t)cos(wt)dt - j∫s(t)sin(wt)dt form? I have no idea. I'm sure the solution is much simpler than I think it is.
 
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Nobody has any clue? I'm still stuck. I'm studying for an Electronics Math exam and this question (from a past exam) is really stumbling me.
 

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