Which Term to Use for Limit Comparison Test?

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Discussion Overview

The discussion revolves around the application of the limit comparison test in determining the convergence of a series, specifically focusing on the appropriate term to use for comparison and the implications of the test's results.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant presents a series, 3/(n(2^(n-1))), and seeks guidance on which term to use for the limit comparison test after successfully applying the ratio test.
  • Another participant questions whether a limit comparison test result of infinity would still indicate convergence if compared to a known convergent series.
  • A clarification is provided regarding the limit comparison test, emphasizing that it requires the limit of the quotient of two positive sequences to exist finitely and not equal zero for convergence conclusions.
  • The original question is refined to specifically ask if a limit comparison test result of infinity, when compared to a convergent series, implies the convergence of the original series.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the implications of a limit comparison test result of infinity, indicating that the discussion remains unresolved on this point.

Contextual Notes

There is a lack of clarity on the conditions under which the limit comparison test can be applied, particularly regarding the interpretation of results that evaluate to infinity.

hivesaeed4
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I'm given the following:
3/(n(2^(n-1)))
I have to determine convergence using the limit comparison test. I've proved its convergent using the ratio test but am struggling with which term do I divide the above for the limit comparison test. Help?
 
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Don't bother replying. I figured it out.
 
I have just one question. Suppose the limit comparison test evaluates to infinity. Would it still prove convergence?
 
hivesaeed4 said:
I have just one question. Suppose the limit comparison test evaluates to infinity. Would it still prove convergence?


Either you're asking something else or you're confusing the limit comparison test: this test tells you that if the limit of the quotient of two positive sequences exists finitely and is NOT zero, then the series whose general term is one of the seq's converges iff the series whose general term is the other seq. converges...so what's your question?

DonAntonio
 
Sorry. I should have been clearer. The question was if the limit comparison test evaluates to infinity and we used a series whose general term was known to be convergent then the series whose general term's convergence we have to determine, is it also convergent. You answered that question by stating the finite part. Thanks
 

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