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Differential EquationsSuperchallengeBoundary Values & Fourier Series

Boundary Values & Fourier Series · Superchallenge problem

Find the Fourier series of f(x)=x(π2−x2)f(x) = x(\pi^2 - x^2) on [−π,π][-\pi,\pi] and use Parseval's identity 1π∫−ππf2 dx=a022+∑(an2+bn2)\dfrac1\pi\displaystyle\int_{-\pi}^{\pi}f^2\,dx = \dfrac{a_0^2}{2} + \sum(a_n^2 + b_n^2) to find ∑n=1∞1n6\displaystyle\sum_{n=1}^{\infty}\dfrac{1}{n^6}.