Use the Fast Fourier Transform to find the discrete Fourier coefficients for the the following functions using the indicated number of sample points. Carefully indicate each step in your analysis.
(a) $\frac{x}{\pi}, n=4$
(b) $\sin x, n=8$;
(c) $|x-\pi|, n=8$;
(d) $\operatorname{sign}(x-\pi), n=16$.