Lebl-Basic-Analysis-I · Problem 2.2.12

Sequences and Series

Mathematics · facts-about-limits-of-sequences

Problem

Let {an}n=1∞\{a_n\}_{n=1}^\infty and {bn}n=1∞\{b_n\}_{n=1}^\infty be sequences. a) Suppose {an}n=1∞\{a_n\}_{n=1}^\infty is bounded and {bn}n=1∞\{b_n\}_{n=1}^\infty converges to 0. Show that {anbn}n=1∞\{a_n b_n\}_{n=1}^\infty converges to 0. b) Find an example where {an}n=1∞\{a_n\}_{n=1}^\infty is unbounded, {bn}n=1∞\{b_n\}_{n=1}^\infty converges to 0, and {anbn}n=1∞\{a_n b_n\}_{n=1}^\infty is not convergent. c) Find an example where {an}n=1∞\{a_n\}_{n=1}^\infty is bounded, {bn}n=1∞\{b_n\}_{n=1}^\infty converges to some x≠0x \neq 0, and {anbn}n=1∞\{a_n b_n\}_{n=1}^\infty is not convergent.

Related theory

Browse the problem library