Let $(x_n)_{n \in \mathbb{N}}$ a real convergent sequence to a number $l$. We can prove that $(\left| x_n - l\right|)_{n \in \mathbb{N}}$ is ultimately monotone?
Coverging sequences and monotonicity
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sequences-and-series
convergence-divergence
2 Answers
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No, we cannot. For example, let $x_n=1/n$ if $n$ is odd, and $2/n$ if $n$ is even.
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No, the sequence $ \frac13, \frac12, \frac15, \frac14, \frac17, \frac16, \ldots $ converges to $0$ but is never monotonic.