Using ratio test to test conditional convergence?

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SUMMARY

The discussion centers on the application of the ratio test in determining the convergence of series, specifically conditional convergence. It is established that if the limit of the ratio test equals 1, the series may be conditionally convergent, but the test does not provide definitive information. Additionally, if the limit is greater than 1, the series is divergent, while a limit less than 1 indicates absolute convergence. The key takeaway is that a limit of 1 does not guarantee conditional convergence, as the ratio test may not yield a limit at all.

PREREQUISITES
  • Understanding of series convergence concepts
  • Familiarity with the ratio test in calculus
  • Knowledge of absolute and conditional convergence
  • Basic mathematical analysis skills
NEXT STEPS
  • Study the implications of the ratio test in more depth
  • Explore examples of conditionally convergent series
  • Learn about alternative convergence tests, such as the root test
  • Investigate the behavior of series when the ratio test is inconclusive
USEFUL FOR

Students studying calculus, mathematics educators, and anyone seeking to deepen their understanding of series convergence and the ratio test.

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Homework Statement


So what I was taught was that if the lim of the ratio test is the series is always absolutely convergent. If it is >1 the series is always divergent. But if it is =1 then we don't know. So would that mean that all conditionally convergent series would have a limit = 1? I am confused :s

Thanks!
 
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Yes, if the ratio test applied to conditional convergent series exists, then it must be 1. On the other hand, the ratio test might not give you a limit at all. In that case the series can do anything it wants to.
 

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