Use the element method for proving that a set equals the empty set to prove the following statement. (Assume that all sets are subsets of a universal set U.) If U denotes a universal set, then UC = ø. Proof by contradiction: Consider the sentences in the following scrambled list. But, by definition of a universal set, U contains all elements under discussion, and so x E U. So, by definition of complement x E U. Let U be a universal set and suppose Uº = Ø. Let U be a universal set and suppose UC ± Ø. Then there exists an element x in UC. Thus x EU and x € U, which is a contradiction. So, by definition of complement x ¢ U. But, by definition of a universal set, UC contains no elements. We construct the proof by selecting appropriate sentences from the list and putting them in the correct order. 1. Let U be a universal set and suppose UC = Ø. 2. Let U be a universal set and suppose UC = Ø. 3. ---Select--- 4. ---Select--- 5. Thus x e U and x ¢ U, which is a contradiction. 6. Hence the supposition is false, and so UC = ø.

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
Question

how do i solve 1-4

### Proof by Contradiction: Universal Set and Empty Set

**Statement to Prove:**
If \( U \) denotes a universal set, then \( U^C = \emptyset \).

**Method of Proof:**
The element method for proving that a set equals the empty set through contradiction.

**Scrambled Sentences:**
Consider the sentences in the following scrambled list:
1. But, by definition of a universal set, \( U \) contains all elements under discussion, and so \( x \in U \).
2. So, by definition of complement \( x \notin U \).
3. Let \( U \) be a universal set and suppose \( U^C = \emptyset \).
4. Let \( U \) be a universal set and suppose \( U^C \neq \emptyset \).
5. Then there exists an element \( x \in U^C \).
6. Thus \( x \in U \) and \( x \notin U \), which is a contradiction.
7. So, by definition of complement \( x \notin U \).
8. But, by definition of a universal set, \( U^C \) contains no elements.

**Proof Construction:**
We construct the proof by selecting appropriate sentences from the list and putting them in the correct order.

1. Let \( U \) be a universal set and suppose \( U^C \neq \emptyset \). ❌
2. Let \( U \) be a universal set and suppose \( U^C \neq \emptyset \). ❌
3. *---Select---*
4. *---Select---*
5. Thus \( x \in U \) and \( x \notin U \), which is a contradiction. ✅
6. Hence the supposition is false, and so \( U^C = \emptyset \).

**Explanation of Steps:**
1. **Correct Step:** Let \( U \) be a universal set and suppose \( U^C \neq \emptyset \).
2. **Correct Step:** Then there exists an element \( x \in U^C \).
3. **Correct Step:** By definition of complement \( x \notin U \).
4. **Correct Step:** But, by definition of a universal set, \( U \) contains all elements under discussion, and so \( x \in U \).
5. **Correct Step:** Thus
Transcribed Image Text:### Proof by Contradiction: Universal Set and Empty Set **Statement to Prove:** If \( U \) denotes a universal set, then \( U^C = \emptyset \). **Method of Proof:** The element method for proving that a set equals the empty set through contradiction. **Scrambled Sentences:** Consider the sentences in the following scrambled list: 1. But, by definition of a universal set, \( U \) contains all elements under discussion, and so \( x \in U \). 2. So, by definition of complement \( x \notin U \). 3. Let \( U \) be a universal set and suppose \( U^C = \emptyset \). 4. Let \( U \) be a universal set and suppose \( U^C \neq \emptyset \). 5. Then there exists an element \( x \in U^C \). 6. Thus \( x \in U \) and \( x \notin U \), which is a contradiction. 7. So, by definition of complement \( x \notin U \). 8. But, by definition of a universal set, \( U^C \) contains no elements. **Proof Construction:** We construct the proof by selecting appropriate sentences from the list and putting them in the correct order. 1. Let \( U \) be a universal set and suppose \( U^C \neq \emptyset \). ❌ 2. Let \( U \) be a universal set and suppose \( U^C \neq \emptyset \). ❌ 3. *---Select---* 4. *---Select---* 5. Thus \( x \in U \) and \( x \notin U \), which is a contradiction. ✅ 6. Hence the supposition is false, and so \( U^C = \emptyset \). **Explanation of Steps:** 1. **Correct Step:** Let \( U \) be a universal set and suppose \( U^C \neq \emptyset \). 2. **Correct Step:** Then there exists an element \( x \in U^C \). 3. **Correct Step:** By definition of complement \( x \notin U \). 4. **Correct Step:** But, by definition of a universal set, \( U \) contains all elements under discussion, and so \( x \in U \). 5. **Correct Step:** Thus
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 2 steps with 2 images

Blurred answer
Knowledge Booster
Linear Equations
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
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,