List of top Mathematics Questions on Fourier series

Fourier series of \(x^2,\;0<x<2\) is \[ f(x)=\frac{a_0}{2} +\sum_{n=1}^{\infty}a_n\cos(n\pi x) +\sum_{n=1}^{\infty}b_n\sin(n\pi x), \] then \(b_2=\)

Fourier series of \(x^2,\;0<x<2\) is \[ f(x)=\frac{a_0}{2} +\sum_{n=1}^{\infty}a_n\cos(n\pi x) +\sum_{n=1}^{\infty}b_n\sin(n\pi x), \] then \(b_2=\)

If $f(x) = x^3$, $0 \le x \le 4$, $f(x+4) = f(x)$ $\forall x \in \mathbb{R}$ and the Fourier series of $f(x)$ is $f(x) = \sum_{n=0}^{\infty} \left(a_n \cos \frac{n\pi x}{2} + b_n \sin \frac{n\pi x}{2}\right)$, then $a_0 =$}

The first non-zero Fourier coefficient in the expansion of \( \sin^3(x) \) is: