L33_A
radius of convergence (Conti.) (續.收斂半徑)
The differentiability Theorem (Power Theorem 的微分定理)
Term-by-term integration

L33_B
積分跟微分有相同的收斂半徑，但無相同的收斂區間。
在收斂區間內，Power series 就是本身和的Taylor series