Convergent series. Is my logic correct?

Click For Summary
SUMMARY

The series \(\sum_{n=1}^\infty \frac{x^n}{1+x^n}\) converges for \(x\) in the interval \([0, 1)\) and can be further established to converge for \(x\) in the range \((-1, 1)\). This conclusion is derived from the comparison with the geometric series \(\sum_{n=1}^\infty x^n\), which converges when the common ratio \(r = x < 1\). The discussion confirms the validity of using the ratio test to analyze convergence, reinforcing the established results.

PREREQUISITES
  • Understanding of series convergence, specifically geometric series.
  • Familiarity with the ratio test for series.
  • Basic knowledge of limits and intervals in real analysis.
  • Ability to manipulate and compare series expressions.
NEXT STEPS
  • Study the properties of geometric series and their convergence criteria.
  • Learn about the ratio test and its application in determining series convergence.
  • Explore convergence tests for series beyond the ratio test, such as the root test.
  • Investigate the behavior of series in different intervals, particularly in real analysis.
USEFUL FOR

Mathematics students, educators, and anyone interested in series convergence, particularly in the context of real analysis and calculus.

emilkh
Messages
7
Reaction score
0
Show [tex] \sum_1^\infty\frac{x^n}{1+x^n}[/tex] converges when x is in [0,1)
[tex] \sum_1^\infty\frac{x^n}{1+x^n} = \sum_1^\infty\frac{1}{1+x^n} * x^n <= \sum_1^\infty\frac{1}{1} * x^n = \sum_1^\infty x^n[/tex]

The last sum is g-series, converges since r = x < 1
 
Physics news on Phys.org
Yes, that is correct. In fact, you can say more: the series converges for x in (-1, 1).
 
ratio test?
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 2 ·
Replies
2
Views
4K
Replies
3
Views
2K