Math Problem Statement

If f(x) is differentiable on [a,b] and f(a) = b and f(b) = a, then there exists c between a and b such that f'(c) = -1.

Solution

The question involves analyzing a mathematical statement based on the Mean Value Theorem (MVT) or Rolle's Theorem.

We are given:

  • f(x)f(x) is differentiable on [a,b][a, b].
  • f(a)=bf(a) = b and f(b)=af(b) = a.

The claim is that there exists a c(a,b)c \in (a, b) such that f(c)=1f'(c) = -1.

Verification:

  1. By the Mean Value Theorem (MVT), if f(x)f(x) is continuous on [a,b][a, b] and differentiable on (a,b)(a, b), there exists c(a,b)c \in (a, b) such that: f(c)=f(b)f(a)ba.f'(c) = \frac{f(b) - f(a)}{b - a}.

  2. Substituting f(a)=bf(a) = b and f(b)=af(b) = a into the formula: f(c)=abba.f'(c) = \frac{a - b}{b - a}.

  3. Simplify: f(c)=1.f'(c) = -1.

This shows that the statement is TRUE because it directly follows from the Mean Value Theorem.

Would you like further clarification on the reasoning or additional examples?

Here are 5 related questions to explore further:

  1. What are the conditions for the Mean Value Theorem to be applicable?
  2. How does Rolle's Theorem relate to the Mean Value Theorem?
  3. Can a function violate this statement if it's not differentiable on (a,b)(a, b)?
  4. What happens if f(a)=f(b)f(a) = f(b) in this context?
  5. How can this theorem be applied to real-world problems involving rates of change?

Tip: Always verify the conditions of a theorem before applying it to ensure the function satisfies continuity and differentiability.

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Math Problem Analysis

Mathematical Concepts

Differentiability
Continuity
Mean Value Theorem (MVT)

Formulas

f'(c) = (f(b) - f(a)) / (b - a)

Theorems

Mean Value Theorem

Suitable Grade Level

Grades 11-12 or early college