Absolute and Conditional Convergence Problem

In summary, after attempting to use the ratio test and root test to determine absolute and conditional convergence of the series \sum\left(-1\right)^{k+1}\frac{k^{k}}{k!}, it was found that these tests were inconclusive. However, the divergence test was then applied, revealing that the term goes to infinity and the series diverges.
  • #1
atarr3
76
0

Homework Statement



Test the series for (a) absolute convergence, and (b) conditional convergence.

[tex]\sum\left(-1\right)^{k+1}\frac{k^{k}}{k!}[/tex]

Homework Equations





The Attempt at a Solution



So I tried taking the absolute value and then applying the ratio test, which, after simplifying gives me [tex]\frac{\left(k+1\right)^{k}}{k^{k}}[/tex] and then using the root test, but that simplifies to [tex]\frac{k+1}{k}[/tex] which converges at 1 and therefore those tests are inconclusive.
 
Physics news on Phys.org
  • #2
Is k^k > k! true for all k?
 
  • #3
Ahhhhh... divergence test. Wow that was a lot easier than I thought it was. So the term goes to infinity and the series diverges. Thank you so much for your help!
 

Related to Absolute and Conditional Convergence Problem

1. What is the difference between absolute and conditional convergence?

Absolute convergence refers to a series that converges regardless of the order in which the terms are added. Conditional convergence refers to a series that converges only when the terms are added in a certain order.

2. How do I determine if a series is absolutely or conditionally convergent?

To determine absolute convergence, the series must pass the absolute convergence test, which states that the absolute value of each term in the series must be less than or equal to the corresponding term in a convergent series. To determine conditional convergence, the series must pass the conditional convergence test, which states that the series must be convergent, but not absolutely convergent.

3. Can a series be both absolutely and conditionally convergent?

No, a series can only be either absolutely convergent or conditionally convergent. If a series is absolutely convergent, it automatically implies that it is also conditionally convergent.

4. What is the importance of knowing whether a series is absolutely or conditionally convergent?

Knowing whether a series is absolutely or conditionally convergent is important in determining the behavior and properties of the series. It can also help in determining whether certain mathematical operations can be performed on the series.

5. Are there any real-life applications of the absolute and conditional convergence problem?

Yes, the concept of absolute and conditional convergence is used in various fields such as physics, engineering, and economics. For example, in physics, these concepts are used in the study of alternating current circuits and in solving differential equations. In economics, they are used in analyzing financial markets and in making investment decisions.

Similar threads

  • Calculus and Beyond Homework Help
Replies
2
Views
762
  • Calculus and Beyond Homework Help
Replies
2
Views
267
  • Calculus and Beyond Homework Help
Replies
1
Views
334
  • Calculus and Beyond Homework Help
Replies
3
Views
458
  • Calculus and Beyond Homework Help
Replies
3
Views
525
  • Calculus and Beyond Homework Help
Replies
3
Views
1K
  • Calculus and Beyond Homework Help
Replies
4
Views
399
  • Calculus and Beyond Homework Help
Replies
5
Views
439
  • Calculus and Beyond Homework Help
Replies
5
Views
1K
  • Calculus and Beyond Homework Help
Replies
8
Views
309
Back
Top