Parseval's Identity, Fourier Series, and Solving this Classic Pi Formula

To celebrate #PiDay we solve the Basel Problem - that the sum of reciprocals of square naturals is pi^2/6 - using techniques from Fourier Analysis, in particular Parseval's Identity, which is a sort of infinite dimensional analog of Pythagoras.

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0:00 The Basel Problem
1:06 Fourier Series Refresher
3:22 Parseval's Identity
5:13 Inner Products & Generalized Pythagoras
9:46 The proof that n^2/6=1/1+1/4+1/9...


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