Determine ue ther He tollowing series convrge absolutely, converge condlitonally ,or ddi serge. E (-Fと

Calculus: Early Transcendentals
8th Edition
ISBN:9781285741550
Author:James Stewart
Publisher:James Stewart
Chapter1: Functions And Models
Section: Chapter Questions
Problem 1RCC: (a) What is a function? What are its domain and range? (b) What is the graph of a function? (c) How...
icon
Related questions
Question
### Series Convergence Analysis

**Problem Statement:**
Determine whether the following series converge absolutely, converge conditionally, or diverge:

\[
\sum_{k=1}^{\infty} (-1)^k e^{-k}
\]

**Explanation:**
- The given mathematical expression is an infinite series starting from \(k = 1\) to infinity.
- Each term in the series is given by the general term \((-1)^k e^{-k}\).

**Steps to Determine Convergence:**

1. **Identify the Series Type:**
   - The series is an alternating series because it has a factor of \((-1)^k\), which causes the signs of the terms to alternate.

2. **Check Absolute Convergence:**
   - To check if the series converges absolutely, consider the absolute value of the terms:
     \[
     \left| (-1)^k e^{-k} \right| = e^{-k}
     \]
     - The series \(\sum_{k=1}^{\infty} e^{-k}\) is a geometric series with a common ratio \(r = e^{-1}\), which is less than 1.
     - A geometric series converges if \(|r| < 1\).

3. **Check Conditional Convergence:**
   - If the series converges absolutely, it also converges conditionally. However, if it does not converge absolutely, we should check for conditional convergence using the Alternating Series Test.
     - The Alternating Series Test requires:
       1. The absolute value of the terms \(e^{-k}\) must be monotonically decreasing.
       2. The limit of \(e^{-k}\) as \(k\) approaches infinity must be 0.
     - Both these conditions are satisfied for the series \(\sum_{k=1}^{\infty} (-1)^k e^{-k}\).

4. **Conclusion:**
   - Since the series \(\sum_{k=1}^{\infty} e^{-k}\) converges (as a geometric series), the given series converges absolutely.
   
Therefore, the series \(\sum_{k=1}^{\infty} (-1)^k e^{-k}\) converges absolutely.
Transcribed Image Text:### Series Convergence Analysis **Problem Statement:** Determine whether the following series converge absolutely, converge conditionally, or diverge: \[ \sum_{k=1}^{\infty} (-1)^k e^{-k} \] **Explanation:** - The given mathematical expression is an infinite series starting from \(k = 1\) to infinity. - Each term in the series is given by the general term \((-1)^k e^{-k}\). **Steps to Determine Convergence:** 1. **Identify the Series Type:** - The series is an alternating series because it has a factor of \((-1)^k\), which causes the signs of the terms to alternate. 2. **Check Absolute Convergence:** - To check if the series converges absolutely, consider the absolute value of the terms: \[ \left| (-1)^k e^{-k} \right| = e^{-k} \] - The series \(\sum_{k=1}^{\infty} e^{-k}\) is a geometric series with a common ratio \(r = e^{-1}\), which is less than 1. - A geometric series converges if \(|r| < 1\). 3. **Check Conditional Convergence:** - If the series converges absolutely, it also converges conditionally. However, if it does not converge absolutely, we should check for conditional convergence using the Alternating Series Test. - The Alternating Series Test requires: 1. The absolute value of the terms \(e^{-k}\) must be monotonically decreasing. 2. The limit of \(e^{-k}\) as \(k\) approaches infinity must be 0. - Both these conditions are satisfied for the series \(\sum_{k=1}^{\infty} (-1)^k e^{-k}\). 4. **Conclusion:** - Since the series \(\sum_{k=1}^{\infty} e^{-k}\) converges (as a geometric series), the given series converges absolutely. Therefore, the series \(\sum_{k=1}^{\infty} (-1)^k e^{-k}\) converges absolutely.
Expert Solution
steps

Step by step

Solved in 2 steps with 2 images

Blurred answer
Knowledge Booster
Series
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, calculus and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Calculus: Early Transcendentals
Calculus: Early Transcendentals
Calculus
ISBN:
9781285741550
Author:
James Stewart
Publisher:
Cengage Learning
Thomas' Calculus (14th Edition)
Thomas' Calculus (14th Edition)
Calculus
ISBN:
9780134438986
Author:
Joel R. Hass, Christopher E. Heil, Maurice D. Weir
Publisher:
PEARSON
Calculus: Early Transcendentals (3rd Edition)
Calculus: Early Transcendentals (3rd Edition)
Calculus
ISBN:
9780134763644
Author:
William L. Briggs, Lyle Cochran, Bernard Gillett, Eric Schulz
Publisher:
PEARSON
Calculus: Early Transcendentals
Calculus: Early Transcendentals
Calculus
ISBN:
9781319050740
Author:
Jon Rogawski, Colin Adams, Robert Franzosa
Publisher:
W. H. Freeman
Precalculus
Precalculus
Calculus
ISBN:
9780135189405
Author:
Michael Sullivan
Publisher:
PEARSON
Calculus: Early Transcendental Functions
Calculus: Early Transcendental Functions
Calculus
ISBN:
9781337552516
Author:
Ron Larson, Bruce H. Edwards
Publisher:
Cengage Learning