Problem 1 Let {ak} and {bk} be sequences of positive real numbers. Assume that lim “k...
(4) Let Σ ak and Σ bk be series with positive terms. The limit comparison test applies when a/bk L0; suppose for this problem that ak/bk0. (a) Show that if Σ bk converges, then Σ ak converges. Hint: remember we can delete finitely many terms from the series and not affect convergence. Use the fact a/bk0 to truncate the series at a convenient point. (b) Show that if ak diverges, then bk diverges. (c) Show by example that if Σ...
3.) Let ak E R with ak > 0 for all k E N. Suppose Σ㎞iak converges. Show that Σί1bk (By definition, for a sequence (ck), we say liCkoo if, for all M ER with Hint: Show that there exists (Ni))ไ1 with N > Nj for all j E N, such that bk there exists a sequence (bk)k of real numbers such that lim converges = oo and M >0, there exists N E N such that ck > M...
5. Let {xn} and {yn} be sequences of real numbers such that x1 = 2 and y1 = 8 and for n = 1,2,3,··· x2nyn + xnyn2 x2n + yn2 xn+1 = x2 + y2 and yn+1 = x + y . nn nn (a) Prove that xn+1 − yn+1 = −(x3n − yn3 )(xn − yn) for all positive integers n. (xn +yn)(x2n +yn2) (b) Show that 0 < xn ≤ yn for all positive integers n. Hence, prove...
lim k+ +oo For the series k, let L Which of the following statements does NOT follow from the Ratio Test? The series diverges when L> 1 The series converges when L < 1 The series converges when L 0 None of the other options The series diverges when L 1.
{x_n} and {y_n} are sequences of positive real numbers AC fn→oo > O, prove tha m in yn lim xn 0 implies lim yn_0
Determine whether the following series converges. 0 Σ 8(-1) 2k + 5 k=0 Let ak 20 represent the magnitude of the terms of the given series. Select the correct choice below and fill in the answer box(es) to complete your choice. A. The series converges because ak = of k>N for which ak+1 Sak: and for any index N, there are some values of k>N for which ak+1 ? ak and some values B. The series converges because ak =...
3) Let (an)2- be a sequence of real numbers such that lim inf lanl 0. Prove that there exists a subsequence (mi)2-1 such that Σ . an, converges に1
18. If ai, az, as,... is a bounded sequence of real numbers, define lim sup an (also denoted lim an) to be --+ n+ l.u.b. {z ER: an > & for an infinite number of integers n} and define lim inf an (also denoted lim an) to be g.l.b. {ER: An <for an infinite number of integers n}. Prove that lim inf an Slim sup an, with the equality holding if and only if the sequence converges. 19. Let ai,...
please i need the question (m) (n)(o) for the detailed proof and example ! thanks ! Prove that the given statements are true concerning the two sequences of real numbers (an) and (b. 0 and limn→” an-L > 0, then (m) If an, bn lim an) (lim supbn) lim sup (anbn) - (n) If an > 0 and bn > 0 and if both lim supn→ooan and lim supn→oobn are either finite or infinite, then lim sup,-,(anbn) < (lim sup,-o...
(Exercise 4.13, reordered) Given a series ΣΧί ak, let 8,-Ση-i ak. Σχί ak is Cesaro summable if S1 + 82 +... +Sn lim n-+o converges. (a) Give an example of a series Σ00i ak that is Cesaro sum mable but not convergent (b) Prove that if 1 ak converges, then it is Cèsaro summable. Hint: Say the sequence of partial sums sn → L. Try to prove that =1 8k → L by showing and then splitting the latter sum...