Basic Analysis I — Real Analysis · Problem 2.1.7

Sequences and Series — Jiri Lebl

Mathematics — Real Analysis · sequences-and-limits

Problem

Let {xn}n=1∞\{x_n\}_{n=1}^\infty be a sequence. a) Show that lim⁡n→∞xn=0\lim_{n\to\infty} x_n = 0 (that is, the limit exists and is zero) if and only if lim⁡n→∞∣xn∣=0\lim_{n\to\infty} |x_n| = 0. b) Find an example such that {∣xn∣}n=1∞\{|x_n|\}_{n=1}^\infty converges and {xn}n=1∞\{x_n\}_{n=1}^\infty diverges.

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