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

In summary, the conversation discusses the convergence or divergence of the series ln((n!e^n)/n^(n+1/2)). One person suggests using the Cauchy criterium with the Striling formula, which shows that the series is divergent. Another person mentions using the p-series test for further insight.
  • #1
garryh22
4
0
[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
 
Physics news on Phys.org
  • #2
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
 
  • #3
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
 

1. What is an infinite series convergence test?

An infinite series convergence test is a mathematical method used to determine whether an infinite series (a sum of infinitely many terms) converges or diverges. It is important in various areas of mathematics, such as calculus and numerical analysis.

2. How does the ln((n!e^n)/n^(n+1/2)) series convergence test work?

This convergence test is known as the ratio test, which compares the absolute value of the ratio of consecutive terms of the series to a limit. In this case, the limit is 1. If the ratio is less than 1, the series converges. If the ratio is greater than 1, the series diverges. If the ratio is equal to 1, the test is inconclusive and another test must be used.

3. What is the significance of the ln((n!e^n)/n^(n+1/2)) series convergence test?

This series convergence test is important because it can be used to determine the convergence or divergence of a wide range of series, including power series, Taylor series, and infinite products. It is also often used in proving the convergence of more complex series.

4. Can the ln((n!e^n)/n^(n+1/2)) series convergence test be used for all series?

No, this convergence test can only be used for series that have positive terms and whose terms approach 0 as n approaches infinity. If these conditions are not met, then another convergence test must be used.

5. Are there any other commonly used convergence tests for infinite series?

Yes, there are several other commonly used convergence tests, such as the integral test, comparison test, and root test. Each test has its own conditions and limitations, so it is important to understand and apply the correct test for a given series.

Similar threads

  • Calculus and Beyond Homework Help
Replies
2
Views
169
  • Calculus and Beyond Homework Help
Replies
1
Views
231
  • Calculus and Beyond Homework Help
Replies
2
Views
703
  • Calculus and Beyond Homework Help
Replies
17
Views
1K
Replies
8
Views
1K
  • Calculus and Beyond Homework Help
Replies
22
Views
3K
  • Calculus and Beyond Homework Help
Replies
7
Views
991
  • Calculus and Beyond Homework Help
Replies
3
Views
401
  • Calculus and Beyond Homework Help
Replies
7
Views
943
  • Calculus and Beyond Homework Help
Replies
2
Views
367
Back
Top