Given $f(x)=\left\{\begin{aligned} x, & 0<x<1 \\-2, & 1<x<2 \end{aligned}\right.$
(a) Sketch at least three periods of the graph of the function represented by the sine series for $f(x)$. Without finding any series, answer the following questions:
(b) To what value does the sine series in (a) converge at $x=1 ?$ At $x=2 ?$ At $x=0$ ? At $x=-1$
(c) If the given function is continued with period 2 and then is represented by a complex exponential series $\sum_{\pi}^{\alpha}-\infty \bar{i}_{n} e^{i n \pi x}$, what is the value of $\sum_{n^{-}-i x}^{x}\left|c_{n}\right|^{2}$ ?