1) a_n = (-2)^n/3n!
Determine whether the sequence converges or diverges. If it converges, find the limit.

2) Determine whether the series is convergent or divergent. If it is convergent, find its sum.


呢個應該係geometric series? 我試過用兩種方法拆開
1)a=6, r=5/6, sum=36
2)a=5, r=5/6, sum=30
但都係計唔到25 (用wolfram計)

數神召喚