Math Problem Statement

Determine whether Rolle's theorem can be applied to f on the closed interval [a, b]. Select all that apply. Given: f(x) = -x^2 + 2x on the interval [0, 2].

Solution

Let's go through the problem step-by-step to determine if Rolle's theorem can be applied and, if it can, find the value(s) of cc where f(c)=0f'(c) = 0.

Step 1: Understanding Rolle's Theorem Requirements

Rolle's theorem applies to a function f(x)f(x) on a closed interval [a,b][a, b] if:

  1. Continuity on the closed interval [a,b][a, b].
  2. Differentiability on the open interval (a,b)(a, b).
  3. Equal values at the endpoints: f(a)=f(b)f(a) = f(b).

Given:

  • f(x)=x2+2xf(x) = -x^2 + 2x
  • Interval [0,2][0, 2]

We will verify if f(x)f(x) satisfies these conditions.

Step 2: Verify Continuity

The function f(x)=x2+2xf(x) = -x^2 + 2x is a polynomial, and polynomials are continuous everywhere. Therefore, f(x)f(x) is continuous on [0,2][0, 2].

Step 3: Verify Differentiability

Since f(x)f(x) is a polynomial, it is also differentiable everywhere, including on the open interval (0,2)(0, 2).

Step 4: Check if f(0)=f(2)f(0) = f(2)

Now, let's calculate f(0)f(0) and f(2)f(2):

  • f(0)=(0)2+20=0f(0) = -(0)^2 + 2 \cdot 0 = 0
  • f(2)=(2)2+22=4+4=0f(2) = -(2)^2 + 2 \cdot 2 = -4 + 4 = 0

Since f(0)=f(2)=0f(0) = f(2) = 0, the third condition is also satisfied.

Conclusion

All three conditions of Rolle's theorem are met, so Rolle's theorem can be applied.

Step 5: Find cc such that f(c)=0f'(c) = 0

  1. First, compute f(x)f'(x): f(x)=x2+2xf(x) = -x^2 + 2x f(x)=2x+2f'(x) = -2x + 2
  2. Set f(x)=0f'(x) = 0 to find the value of cc: 2x+2=0-2x + 2 = 0 2x=22x = 2 x=1x = 1

So, c=1c = 1 is the value in the open interval (0,2)(0, 2) where f(c)=0f'(c) = 0.

Final Answer

  • Rolle's theorem can be applied (select the first option).
  • The value of cc is 11.

Would you like further details or explanations on any specific part of this problem?


Here are five related questions to deepen your understanding:

  1. What are the consequences if f(x)f(x) were not continuous on [a,b][a, b]?
  2. How would you solve this if the function were not differentiable on (a,b)(a, b)?
  3. Can Rolle's theorem be applied to functions that have discontinuities or cusps?
  4. How does Rolle's theorem relate to the Mean Value Theorem?
  5. What if f(a)f(b)f(a) \neq f(b); how does this affect the theorem’s application?

Tip: Always ensure that a function meets all criteria before applying theorems like Rolle's.

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Math Problem Analysis

Mathematical Concepts

Calculus
Polynomial Functions
Continuity
Differentiability

Formulas

f(x) = -x^2 + 2x
f'(x) = -2x + 2

Theorems

Rolle's Theorem

Suitable Grade Level

Grades 11-12