Does the sequence e−(n12)(n+1)100 converge? If yes what is the limit?
What I tried: Expanding
(n+1)100=1+100C1n+100C2n2+100C3n3+⋯+100C100n100
Multiplying each term by e−(n12) and taking limits using L'Hospital Rule we get the limit of the sequence 0, but that is a lengthy and I think it is not a proper approach. [Actually applying L'Hospital rule twice to each term gives the preceding term(I checked it upto [n3e−(n12)] and hence ultimately limit will be 0 because lim(e−(n12))=0]
Can anyone please tell me whether this is a correct method to solve the problem and please suggest me a proper method if there is any. Thank you.
The answer is limit of the sequence is 0
Answer
Yes, the final limit is zero. Note that as n→+∞
e−√n(n+1)100=exp(−√n(1−100ln(n+1)√n)⏟→1)→0
because, for example by using L'Hopital,
limn→+∞ln(n+1)√n=0.
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