Infinite Series Convergence Test: ln((n!e^n)/n^(n+1/2)) [SOLVED]

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SUMMARY

The series ln((n!e^n)/n^(n+1/2)) diverges, confirmed through the application of the Cauchy criterion. The convergence was analyzed using Stirling's formula, which simplifies log(n!) to n*log(n) - n. This reduction leads to the expression ln(1/n)^(1/2), which diverges according to the p-series test. The discussion highlights the importance of Stirling's formula in evaluating series convergence.

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  • Understanding of series convergence tests, specifically the Cauchy criterion.
  • Familiarity with Stirling's formula for approximating factorials.
  • Knowledge of logarithmic properties and their applications in series.
  • Basic concepts of p-series and their convergence criteria.
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  • Study the application of Stirling's formula in greater detail.
  • Learn about the Cauchy convergence test and its implications for series.
  • Explore the properties of p-series and their convergence behavior.
  • Investigate other convergence tests such as the Ratio Test and Root Test.
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garryh22
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[SOLVED] Infinite Series

Homework Statement



ln((n!e^n)/n^(n+1/2))

Homework Equations



Does the series above converge or diverge.

The Attempt at a Solution



I can see that it diverges but I'm looking for the appropriate test to show this
 
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The series is convergent by Cauchy criterium since C(n+1)/C(n)->0 for n>infinity,
as can be easily verified using Striling formula : log(n!) => n*log(n)-n
 
Thanks a great deal. I never heard of the Striling formula till now. I just looked it up, applied it and the expression reduced to ln(1/n)^(1/2) which diverges with p-series. Further insight would be greatly appreciated
 

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