Suppose DCR and f.D R and g:D-R are both uniformly continuous on D. (a) Prove that the function f + g: D-R is uniformly continuous on D. (b) Give a counterexample to show that the function fg: D-R need not be uniformly continuous on D.
Suppose DCR and f.D R and g:D-R are both uniformly continuous on D. (a) Prove that the function f + g: D-R is uniformly continuous on D. (b) Give a counterexample to show that the function fg: D-R need not be uniformly continuous on D.
Algebra & Trigonometry with Analytic Geometry
13th Edition
ISBN:9781133382119
Author:Swokowski
Publisher:Swokowski
Chapter4: Polynomial And Rational Functions
Section4.5: Rational Functions
Problem 50E
Related questions
Question
![## Uniform Continuity Proof and Counterexample
### Statement:
Suppose \( D \subseteq \mathbb{R} \) and functions \( f: D \to \mathbb{R} \) and \( g: D \to \mathbb{R} \) are both uniformly continuous on \( D \).
#### (a) Prove that the function \( f + g: D \to \mathbb{R} \) is uniformly continuous on \( D \).
#### (b) Provide a counterexample to show that the function \( f \cdot g: D \to \mathbb{R} \) need not be uniformly continuous on \( D \).
### Explanation:
- **Uniform Continuity**: A function \( h: D \to \mathbb{R} \) is uniformly continuous on \( D \) if for every \( \epsilon > 0 \), there exists a \( \delta > 0 \) such that for all \( x, y \in D \), \( |x - y| < \delta \) implies \( |h(x) - h(y)| < \epsilon \).
### Tasks:
1. **Proof of Uniform Continuity for Sum of Functions**:
- To prove \( f + g \) is uniformly continuous on \( D \), utilize the uniform continuity of \( f \) and \( g \) on \( D \).
2. **Counterexample for Product of Functions**:
- Find functions \( f \) and \( g \) that are uniformly continuous on \( D \), but whose product \( f \cdot g \) is not uniformly continuous on \( D \).
### Analysis for Educators:
- Encourage students to review the definitions and properties of uniform continuity.
- Discuss the implications of uniform continuity in analysis and real-world problems.
- Guide students through the proof technique required for demonstrating uniform continuity of the sum of functions.
- Illustrate with examples and encourage students to create their own counterexamples for better understanding.
### Graph Explanation (if provided):
If graphs or diagrams were to be present, they would typically illustrate the behavior of functions \( f \) and \( g \) and their sum \( f + g \), showing how their slopes or values remain bounded, underlining the concept of uniform continuity visually. For counterexamples, graphs would show instances where the product \( f \cdot g \) shows non-uniform characteristics.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F87a5eb21-df18-43d0-b53f-a372e6adca02%2F0530a623-bbe8-48e2-bfb1-02949e33a56d%2Ftmnaduy_processed.jpeg&w=3840&q=75)
Transcribed Image Text:## Uniform Continuity Proof and Counterexample
### Statement:
Suppose \( D \subseteq \mathbb{R} \) and functions \( f: D \to \mathbb{R} \) and \( g: D \to \mathbb{R} \) are both uniformly continuous on \( D \).
#### (a) Prove that the function \( f + g: D \to \mathbb{R} \) is uniformly continuous on \( D \).
#### (b) Provide a counterexample to show that the function \( f \cdot g: D \to \mathbb{R} \) need not be uniformly continuous on \( D \).
### Explanation:
- **Uniform Continuity**: A function \( h: D \to \mathbb{R} \) is uniformly continuous on \( D \) if for every \( \epsilon > 0 \), there exists a \( \delta > 0 \) such that for all \( x, y \in D \), \( |x - y| < \delta \) implies \( |h(x) - h(y)| < \epsilon \).
### Tasks:
1. **Proof of Uniform Continuity for Sum of Functions**:
- To prove \( f + g \) is uniformly continuous on \( D \), utilize the uniform continuity of \( f \) and \( g \) on \( D \).
2. **Counterexample for Product of Functions**:
- Find functions \( f \) and \( g \) that are uniformly continuous on \( D \), but whose product \( f \cdot g \) is not uniformly continuous on \( D \).
### Analysis for Educators:
- Encourage students to review the definitions and properties of uniform continuity.
- Discuss the implications of uniform continuity in analysis and real-world problems.
- Guide students through the proof technique required for demonstrating uniform continuity of the sum of functions.
- Illustrate with examples and encourage students to create their own counterexamples for better understanding.
### Graph Explanation (if provided):
If graphs or diagrams were to be present, they would typically illustrate the behavior of functions \( f \) and \( g \) and their sum \( f + g \), showing how their slopes or values remain bounded, underlining the concept of uniform continuity visually. For counterexamples, graphs would show instances where the product \( f \cdot g \) shows non-uniform characteristics.
Expert Solution
![](/static/compass_v2/shared-icons/check-mark.png)
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
This is a popular solution!
Trending now
This is a popular solution!
Step by step
Solved in 3 steps with 27 images
![Blurred answer](/static/compass_v2/solution-images/blurred-answer.jpg)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, advanced-math and related others by exploring similar questions and additional content below.Recommended textbooks for you
Algebra & Trigonometry with Analytic Geometry
Algebra
ISBN:
9781133382119
Author:
Swokowski
Publisher:
Cengage
Algebra & Trigonometry with Analytic Geometry
Algebra
ISBN:
9781133382119
Author:
Swokowski
Publisher:
Cengage