Hi
i solve a problem about the convergence/divergence of a sequence ..
and i use the trick which in the attachment ..
is my solution correct ?
Yes that is true.
So for any spectators what is going on is that TWiX is just making the observation that if converges it is necessary for . And of course there are a lot of ways to prove that converges thaty may be easier than actually computing .
Example: Compute
Solution: Note that
Therefore converges by the ratio test. Thus by definition