Determining Divergence or Convergence in Series

Click For Summary
SUMMARY

The forum discussion focuses on determining the convergence or divergence of the series \(\sum \frac{2n^{2}+3n}{\sqrt{5+n^{5}}}\) from \(n=1\) to infinity. The user attempted both the Ratio Test and the Limit Comparison Test but encountered inconsistencies in their results. The consensus suggests breaking the series into two parts: analyzing \(\sum \frac{2n^{2}}{\sqrt{5+n^{5}}}\) to establish convergence, as the second term \(\sum \frac{3n}{\sqrt{5+n^{5}}}\) is smaller and will not affect the overall convergence.

PREREQUISITES
  • Understanding of series convergence tests, specifically the Ratio Test and Limit Comparison Test.
  • Familiarity with limits and asymptotic behavior of functions as \(n\) approaches infinity.
  • Knowledge of polynomial and radical expressions in calculus.
  • Ability to manipulate and simplify algebraic expressions for series analysis.
NEXT STEPS
  • Study the application of the Ratio Test in greater detail, focusing on its limitations and conditions.
  • Learn about the Limit Comparison Test and its effectiveness in determining series convergence.
  • Explore techniques for breaking down complex series into simpler components for analysis.
  • Investigate the behavior of polynomial functions divided by radical expressions as \(n\) approaches infinity.
USEFUL FOR

Students studying calculus, particularly those focusing on series convergence, as well as educators and tutors seeking to clarify convergence tests and their applications.

badirishluck
Messages
6
Reaction score
0

Homework Statement


\sum (2n^{2}+3n)/\sqrt{5+n^{5}}
index n=1 to infinity

Homework Equations





The Attempt at a Solution


I tried both the Ratio Test (limit as n goes to infinity of a_{n+1}/a_{n}) and the Limit comparison test (limit as n goes to infinity of a_{n}/ b_{n}) but wasn't able to come up with the same answer from the two tests. What am I doing wrong?
Does it converge or diverge? How?
 
Physics news on Phys.org
try breaking it into 2 pieces and see what you can do with the individual pieces, see if
\sum (2n^{2})/\sqrt{5+n^{5}}
converges, if it does then the whole thing does since the 2nd term is smaller, if it doesn't then the whole thing does not converge.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
14
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K