1.62 Use the following steps to prove that the sequence n has no convergent subsequences if and only if |xn| →∞as nx. a) Suppose that the sequence xn has no convergent subsequences. Let M > 0. Prove that there exist at most finitely many values of n such that In E[-M, M]. Explain why this implies |xn| →∞ as nx. b) Suppose an →∞ as n → ∞o. Show that xn has no convergent subse- quence. (Hint: Exercise 1.61 may help.)

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
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1.62 please
1.61 Suppose In →∞. Prove that every subsequence Ink →∞ as k →∞ as
well. (Hint: The sequence xn is divergent, so it is not enough to quote Theorem
1.5.1.)
1.62 Use the following steps to prove that the sequence n has no convergent
subsequences if and only if |xn| →∞ as n →∞.
a) Suppose that the sequence on has no convergent subsequences. Let M >
0. Prove that there exist at most finitely many values of n such that
In E[-M, M]. Explain why this implies |xn|
→∞ as n →∞.
b) Suppose an →∞ as n → ∞. Show that n has no convergent subse-
quence. (Hint: Exercise 1.61 may help.)
Transcribed Image Text:1.61 Suppose In →∞. Prove that every subsequence Ink →∞ as k →∞ as well. (Hint: The sequence xn is divergent, so it is not enough to quote Theorem 1.5.1.) 1.62 Use the following steps to prove that the sequence n has no convergent subsequences if and only if |xn| →∞ as n →∞. a) Suppose that the sequence on has no convergent subsequences. Let M > 0. Prove that there exist at most finitely many values of n such that In E[-M, M]. Explain why this implies |xn| →∞ as n →∞. b) Suppose an →∞ as n → ∞. Show that n has no convergent subse- quence. (Hint: Exercise 1.61 may help.)
Expert Solution
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In this solution we will discuss and prove that a sequence xn has no convergent subsequences if and only if xn as n.

We know that a sequence yn as n, if for any real number M>0, there exists a natural number n0 such that yn>M for all nn0.

We know that any infinite subset E of a compact set K has a limit point in K.

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