I found a nice problem about series convergence. And would like to share it.
Suppose series +∞∑k=1ak converges absolutely.
1) Found an example when +∞∑k=1ka2k diverges.
2) Suppose that ak is a non increasing sequence. Is it true that +∞∑k=1ka2k converges?
3) Is it true that if ak is a non increasing then +∞∑k=1k2a2k converges?
No comments:
Post a Comment