To find Convergence/Divergence of
and of this one
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You should write for the first, not for the whole sum since it won't depend on . Use the fact that . For the second, could you write the terms with a formula on which appears?
I do not understand how the fact that n! >= n(n-1) can be used for to solve this .
The second one can be simplified to get :-
It is e itself actually, so it converges !
But how do you prove it ?
We have and the sum of the terms of the RHS is telescopic.
For the second series, first try ratio test. If you can't conclude, try Raabe-Duhamel test.
thanks girdav. I shall try it using the tests you mentioned. However this problem was presented before discussion on ratio test or raabe-duhamel test. So i guess we are expected to solve it using comparison test.
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