Series Problem Help: Evaluating \int \frac{\sin x}{x} with Convergence Analysis

  • Thread starter Thread starter courtrigrad
  • Start date Start date
  • Tags Tags
    Series
Click For Summary
SUMMARY

The discussion focuses on evaluating the integral \(\int \frac{\sin x}{x} \) using series expansion and convergence analysis. The series expansion for \(\sin x\) is given as \(\sum_{n=0}^{\infty} (-1)^{n} \frac{x^{2n+1}}{(2n+1)!}\), leading to the conclusion that \(\frac{\sin x}{x} = \sum_{n=0}^{\infty} (-1)^{n} \frac{x^{2n}}{(2n+1)!}\). The integral is determined to be absolutely convergent using the ratio test, confirming that the limit as \(n\) approaches infinity is less than 1.

PREREQUISITES
  • Understanding of Taylor series expansions
  • Familiarity with the concept of absolute convergence
  • Knowledge of the ratio test for series convergence
  • Basic calculus, specifically integration techniques
NEXT STEPS
  • Study the properties of Taylor series and their applications in calculus
  • Learn more about absolute convergence and its implications in series
  • Explore the ratio test in detail, including examples and edge cases
  • Investigate other methods for evaluating improper integrals
USEFUL FOR

Mathematicians, calculus students, and anyone interested in advanced integration techniques and series convergence analysis.

courtrigrad
Messages
1,236
Reaction score
2
I want to evaluate [tex]\int \frac{\sin x}{x}[/tex].

So [tex]\sin x = \sum_{n=0}^{\infty} (-1)^{n} \frac{x^{2n+1}}{(2n+1)!}[/tex]. Therefore [tex]\frac{\sin x}{x} = \sum_{n=0}^{\infty} (-1)^{n} \frac{x^{2n}}{(2n+1)!}[/tex]. So would that mean:

[tex]\int \frac{\sin x}{x} = C + \sum_{n=0}^{\infty} (-1)^{n} \frac{x^{2n+1}}{2n+1(2n+1)!}[/tex] would be absolutely convergent (i.e. [tex]R = \infty[/tex])?

Thanks
 
Physics news on Phys.org
How do you know that series is absolutely convergent?
 
I would use the ratio test [tex]|\frac{ a_{n+1}}{a_{n}}|[/tex]. If the limit as [tex]n\rightarrow \infty[/tex] is less than 1, then the series is absolutely convergent. Ok so I guess it is then.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K
Replies
17
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K