Prove that he interval E = (a, +oo) is an open set in R. (Show all details of your work).

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Question
**Title: Proving the Openness of the Interval \(E = (a, +\infty)\) in \(\mathbb{R}\)**

**Objective:**
To prove that the interval \(E = (a, +\infty)\) is an open set in the real number system \(\mathbb{R}\). We will show all the details of the proof.

**Introduction to Open Sets:**
In the context of real numbers, a set \(S\) is open if, for every point \(x \in S\), there exists an \(\epsilon > 0\) such that the interval \((x - \epsilon, x + \epsilon) \subseteq S\).

**Proof:**
We need to show that for any \(x \in (a, +\infty)\), there exists an \(\epsilon > 0\) for which \((x - \epsilon, x + \epsilon) \subseteq (a, +\infty)\).

1. **Choose any \(x \in (a, +\infty)\).**
   - By definition, \(x > a\).

2. **Define \(\epsilon = \frac{x - a}{2}\).**
   - Since \(x > a\), \(\epsilon\) is positive.

3. **Consider the interval \((x - \epsilon, x + \epsilon)\).**
   - Calculate \(x - \epsilon = x - \frac{x - a}{2} = \frac{2x - x + a}{2} = \frac{x + a}{2}\).
   - Note that \(\frac{x + a}{2} > a\) because \(x > a\).

4. **Verify that \((x - \epsilon, x + \epsilon) \subseteq (a, +\infty)\):**
   - From above, \(x - \epsilon = \frac{x + a}{2} > a\), ensuring \(x - \epsilon > a\).
   - Therefore, the entire interval \((x - \epsilon, x + \epsilon)\) is contained within \((a, +\infty)\).

**Conclusion:**
Since for every \(x \in (a, +\infty)\), there exists an \(\epsilon > 0\) such that \((x - \epsilon, x + \epsilon
Transcribed Image Text:**Title: Proving the Openness of the Interval \(E = (a, +\infty)\) in \(\mathbb{R}\)** **Objective:** To prove that the interval \(E = (a, +\infty)\) is an open set in the real number system \(\mathbb{R}\). We will show all the details of the proof. **Introduction to Open Sets:** In the context of real numbers, a set \(S\) is open if, for every point \(x \in S\), there exists an \(\epsilon > 0\) such that the interval \((x - \epsilon, x + \epsilon) \subseteq S\). **Proof:** We need to show that for any \(x \in (a, +\infty)\), there exists an \(\epsilon > 0\) for which \((x - \epsilon, x + \epsilon) \subseteq (a, +\infty)\). 1. **Choose any \(x \in (a, +\infty)\).** - By definition, \(x > a\). 2. **Define \(\epsilon = \frac{x - a}{2}\).** - Since \(x > a\), \(\epsilon\) is positive. 3. **Consider the interval \((x - \epsilon, x + \epsilon)\).** - Calculate \(x - \epsilon = x - \frac{x - a}{2} = \frac{2x - x + a}{2} = \frac{x + a}{2}\). - Note that \(\frac{x + a}{2} > a\) because \(x > a\). 4. **Verify that \((x - \epsilon, x + \epsilon) \subseteq (a, +\infty)\):** - From above, \(x - \epsilon = \frac{x + a}{2} > a\), ensuring \(x - \epsilon > a\). - Therefore, the entire interval \((x - \epsilon, x + \epsilon)\) is contained within \((a, +\infty)\). **Conclusion:** Since for every \(x \in (a, +\infty)\), there exists an \(\epsilon > 0\) such that \((x - \epsilon, x + \epsilon
Expert Solution
Step 1

Advanced Math homework question answer, step 1, image 1

steps

Step by step

Solved in 2 steps with 2 images

Blurred answer
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,