題組內容

(8) \( (10\%) \) Let \( f{n}:[0,1]\to \mathbb{R} \) be defined by \( f{n}(x) = \frac{x^{2}}{(1 + x^{2})^{n}} \)



(a) Prove that \( \sum{n=1}^{\infty} fn(x) \) is convergent for \( x \in [0,1] \).