Given (x-2)²-Inx=0. Show that it has a solution on [e, 4].

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
This is a 2 part question. Please assist with both images. Thanks so much
**Problem Statement:**

Given the equation \((x-2)^2 - \ln x = 0\).

**Objective:**

Show that this equation has a solution on the interval \([e, 4]\).

**Explanation:**

To solve this problem, you might consider using methods like the Intermediate Value Theorem. This theorem suggests that if a continuous function changes sign over an interval, it must have a root in that interval. Here’s a brief guide on how you might approach this:

1. **Function Definition:**
   Define the function \( f(x) = (x-2)^2 - \ln x \).

2. **Continuity:**
   Check if \( f(x) \) is continuous on \([e, 4]\). Since polynomials and the natural logarithm (\(\ln x\)) are both continuous where defined, and their sum/difference is also continuous, \( f(x) \) is continuous on this interval.

3. **Sign Change:**
   Evaluate \( f(e) \) and \( f(4) \):
   - Calculate \( f(e) = (e-2)^2 - \ln e = (e-2)^2 - 1 \).
   - Calculate \( f(4) = (4-2)^2 - \ln 4 = 4 - \ln 4 \).

   Determine if \( f(e) \) and \( f(4) \) have opposite signs. If they do, by the Intermediate Value Theorem, there is at least one \( c \) in the interval \([e, 4]\) such that \( f(c) = 0 \).

4. **Conclusion:**
   If a sign change is confirmed, then the solution exists within the specified interval.

By verifying these steps, you can show that the given equation has a solution on \([e, 4]\).
Transcribed Image Text:**Problem Statement:** Given the equation \((x-2)^2 - \ln x = 0\). **Objective:** Show that this equation has a solution on the interval \([e, 4]\). **Explanation:** To solve this problem, you might consider using methods like the Intermediate Value Theorem. This theorem suggests that if a continuous function changes sign over an interval, it must have a root in that interval. Here’s a brief guide on how you might approach this: 1. **Function Definition:** Define the function \( f(x) = (x-2)^2 - \ln x \). 2. **Continuity:** Check if \( f(x) \) is continuous on \([e, 4]\). Since polynomials and the natural logarithm (\(\ln x\)) are both continuous where defined, and their sum/difference is also continuous, \( f(x) \) is continuous on this interval. 3. **Sign Change:** Evaluate \( f(e) \) and \( f(4) \): - Calculate \( f(e) = (e-2)^2 - \ln e = (e-2)^2 - 1 \). - Calculate \( f(4) = (4-2)^2 - \ln 4 = 4 - \ln 4 \). Determine if \( f(e) \) and \( f(4) \) have opposite signs. If they do, by the Intermediate Value Theorem, there is at least one \( c \) in the interval \([e, 4]\) such that \( f(c) = 0 \). 4. **Conclusion:** If a sign change is confirmed, then the solution exists within the specified interval. By verifying these steps, you can show that the given equation has a solution on \([e, 4]\).
**Problem Statement:**

Given \( f(x) = (x - 2)^2 - \ln x = 0 \). Show that it has a solution on the interval \([1, 2]\).

**Explanation:**

The problem asks to demonstrate that the equation \( f(x) = (x - 2)^2 - \ln x = 0 \) has at least one solution within the interval \([1, 2]\).

**Approach:**

1. **Substitute Endpoints:**
   - Calculate \( f(1) \) and \( f(2) \) to find the values of the function at the endpoints of the interval.
   
2. **Continuous Function:**
   - Show that \( f(x) \) is continuous on \([1, 2]\). The function \( (x - 2)^2 \) is a polynomial, hence continuous everywhere, and \(-\ln x\) is continuous for \( x > 0 \).

3. **Intermediate Value Theorem (IVT):**
   - Apply the Intermediate Value Theorem, which states that if a function \( f \) is continuous on a closed interval \([a, b]\) and \( f(a) \) and \( f(b) \) have opposite signs, then there exists at least one \( c \) in \((a, b)\) such that \( f(c) = 0 \).

By following these steps, you can show the existence of a solution for the equation within the given interval.
Transcribed Image Text:**Problem Statement:** Given \( f(x) = (x - 2)^2 - \ln x = 0 \). Show that it has a solution on the interval \([1, 2]\). **Explanation:** The problem asks to demonstrate that the equation \( f(x) = (x - 2)^2 - \ln x = 0 \) has at least one solution within the interval \([1, 2]\). **Approach:** 1. **Substitute Endpoints:** - Calculate \( f(1) \) and \( f(2) \) to find the values of the function at the endpoints of the interval. 2. **Continuous Function:** - Show that \( f(x) \) is continuous on \([1, 2]\). The function \( (x - 2)^2 \) is a polynomial, hence continuous everywhere, and \(-\ln x\) is continuous for \( x > 0 \). 3. **Intermediate Value Theorem (IVT):** - Apply the Intermediate Value Theorem, which states that if a function \( f \) is continuous on a closed interval \([a, b]\) and \( f(a) \) and \( f(b) \) have opposite signs, then there exists at least one \( c \) in \((a, b)\) such that \( f(c) = 0 \). By following these steps, you can show the existence of a solution for the equation within the given interval.
Expert Solution
Step 1

Calculus homework question answer, step 1, image 1

steps

Step by step

Solved in 2 steps with 2 images

Blurred answer
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