Bounded sequence, convergent subsequence

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SUMMARY

The discussion focuses on proving that a bounded sequence (an) converges to a limit 'a' if every convergent subsequence of (an) converges to 'a'. The proof involves selecting a subsequence (ank) that converges to 'a' and demonstrating that for sufficiently large indices, the terms of the sequence (an) approach 'a'. This establishes the convergence of the entire sequence (an) to 'a', reinforcing the relationship between bounded sequences and their limits.

PREREQUISITES
  • Understanding of bounded sequences in real analysis
  • Knowledge of subsequences and their convergence properties
  • Familiarity with limits and epsilon-delta definitions
  • Basic proof techniques in mathematical analysis
NEXT STEPS
  • Study the properties of bounded sequences in real analysis
  • Learn about the Bolzano-Weierstrass theorem and its implications
  • Explore the concept of subsequences and their convergence criteria
  • Review epsilon-delta definitions of limits in calculus
USEFUL FOR

Students of real analysis, mathematicians focusing on convergence properties, and educators teaching sequences and limits in calculus.

kathrynag
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Homework Statement



Asssume (an) is a bounded sequence with the property that every convergent subsequence of (an) converges to the same limit a. Show that (an) must converge to a.

Homework Equations





The Attempt at a Solution


If the subsequence converges to a we have , we have:
[tex]\left|ank-a\right|[/tex]=a.
 
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Choose [tex]n_k[/tex] large enough such that [tex]n_k \geq k \geq n_o[/tex]. You should be to use this to show that your sequence converges.
 

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