Alternating Series Test for Convergence

In summary, the conversation discusses whether the given series converges absolutely or conditionally. Applying the alternating series test, it is found that the terms of the series are increasing for n large, indicating that the series diverges.
  • #1
thagzone
1
0

Homework Statement


Does this series converge absolutely or conditionally?

Homework Equations



Series from n=1 to ∞ (-1)^(n+1) * n!/2^n

The Attempt at a Solution



In trying to apply the alternating series test, I have found the following:

1.) n!/2^n > 0 for n>0
2.) Next, in testing to see if n!/2^n is decreasing, I found that (n!/2^n)/((n+1)!/2^(n+1)) < 1 for n large.

Stopping here, this suggests the series diverges in its original form. Is this correct? Thank you!
 
Physics news on Phys.org
  • #2
You have apparently shown the terms of the series are increasing for n large, so they don't go to zero. So yes, you are correct that the series diverges.
 

Related to Alternating Series Test for Convergence

What is the Alternating Series Test for Convergence?

The Alternating Series Test for Convergence is a mathematical test used to determine whether an infinite series, where each term alternates in sign, converges or diverges. It states that if an alternating series satisfies two conditions - the terms decrease in absolute value and approach 0 - then the series is convergent.

How do you apply the Alternating Series Test for Convergence?

To apply the Alternating Series Test for Convergence, you must first check if the series alternates in sign. Then, check if the absolute value of each term decreases as the series progresses. Lastly, check if the limit of the absolute value of the terms approaches 0. If all three conditions are met, the series is convergent.

What is the significance of the Alternating Series Test for Convergence?

The Alternating Series Test for Convergence is significant because it provides a simple and effective way to determine if an alternating series converges or diverges. It is particularly useful for series that do not have a clear pattern or do not fit into other convergence tests.

Can the Alternating Series Test for Convergence be applied to all series?

No, the Alternating Series Test for Convergence can only be applied to alternating series, where the terms alternate in sign. It cannot be applied to series where the terms do not alternate in sign, such as geometric series or harmonic series.

What is the difference between absolute and conditional convergence in alternating series?

Absolute convergence refers to when an alternating series converges regardless of the order of the terms. Conditional convergence refers to when an alternating series only converges when the terms are arranged in a specific order. In other words, absolute convergence guarantees convergence, while conditional convergence does not.

Similar threads

  • Calculus and Beyond Homework Help
Replies
2
Views
251
  • Calculus and Beyond Homework Help
Replies
1
Views
319
  • Calculus and Beyond Homework Help
Replies
2
Views
733
  • Calculus and Beyond Homework Help
Replies
14
Views
1K
  • Calculus and Beyond Homework Help
Replies
17
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
451
  • Calculus and Beyond Homework Help
Replies
7
Views
1K
  • Calculus and Beyond Homework Help
Replies
4
Views
129
  • Calculus and Beyond Homework Help
Replies
5
Views
1K
  • Calculus and Beyond Homework Help
Replies
7
Views
1K
Back
Top