Wednesday, December 18, 2019

calculus - series comparison test for 1/nplog(n)




It is really not obvious to me which values of p make 21nplog(n) converge only using comparison test (general comparison test, limit comparison test).



Am I missing something ? I knew that the series converges for p>1 and diverges for p0 by comparing it with 1/np but that's it.



Edit. I know it can be solved using integral test, cauchy condensation test, etc. but I am just wondering if there is a comparison to some other series that directly results in divergence of this one for p1 (or just p<1 is fine, too.)


Answer



For p<1 compare with 1/nq with $p0lim$


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