Question

the Fourier serier expansion of x2 in the interval -π<x<π is contains
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Answer 1

Answer:

Expand the function f(x) = x2 as Fourier series in the interval [−1, 1]. Hence Deduce that :1 /12 + 1/ 22 + 1 /32 + 1/ 42+ · · · = π2/ 6