Recent content by nernstkizen

Thank you so much! I get it :-p

Sorry, a typo. I mean \sum an diverges.

Thanks for your reply !:-p 1 What I mean is \sum \frac{a_n}{1+na_n} 2 I have already transformed it to \displaystyle \sum \ \frac{a_n}{1+n\,a_n}\ , and I think it won't converges as long as \sum an diverges as n\rightarrow∞

hi~ I think it is impossible to use any test to solve it directly, maybe some tricks should be introduced. btw, it is the exercise 3.11(d) of Principles of Mathematical Analysis (Rudin). Some solutions said that it can either converge or diverge, but I don't agree with them.

suppose an>0, \sumandiverges then what can we say about \sum an/1+nan I think it divergent, but I'm not sure。