摘要: \[\text{ \Large{证明:}} \sum_ {i=1} ^ { \infin } { \frac{1} {i^2} }= { \frac{\pi^2} {6} } \\ \begin{aligned} \text{ \large{已知:}} \sin x = { \sum _{ i=1 阅读全文
posted @ 2025-07-13 12:28 Glowingfire 阅读(23) 评论(0) 推荐(0)