By the Mean Value Theorem, there exists some \(c\) between \(a\) and \(b\) such that
\[
\frac{b^{n+1} - a^{n+1}}{b-a} = (n+1)c^n.
\]
Since \(a < c < b\), it follows that \(c^n < b^n\). Therefore,
\[
(n+1)c^n < (n+1)b^n.
\]
This proves part (a).
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