Suppose a function \( g(x) \) is defined on the interval \( [0,2 \pi] \) and both \( g(x) \) and its derivative \( g^{\prime}(x) \) are continuous and bounded on that interval. In particular, assume \( |g(x)| <M \) and \( \left|g^{\prime}(x)\right|<M \) for all \( x \in[0,2 \pi] \), where M is a constant.
(a) The \( n^{\text {th }} \) sine coefficient of \( g(x) \) is given by:
\[
S_{n}=\int_{0}^{2 \pi} g(x) \cdot \sin (n x) d x
\]
Use integration by parts with \( u=g(x) \) and \( d v=\sin (n x) d x \) to express \( S_{n} \) in terms of \( g^{\prime}(x) \).
(b) Use your result from part (a) to describe what happens to \( S_{n} \) as \( n \rightarrow \infty \). (Hint: Consider bounds like \( \left|g^{\prime}(x) \cdot \cos (n x)\right| \leq M \) and the average behavior of oscillating functions.)
(c) Similarly, consider the \( \mathbf{n}^{\text {th }} \) cosine coefficient:
\[
C_{n}=\int_{0}^{2 \pi} g(x) \cdot \cos (n x) d x
\]
What happens to the values of \( \mathrm{C}_{n} \) as n
\( \infty \) under the same assumptions about \( \mathrm{g}(\mathrm{x}) \) and \( g^{\prime}(x) ? \)
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