Math Problem Statement

Let f(x)=|x|. Which of the following statements is correct?

Question 1 Select one:

The function f satisfies the hypotheses of Rolle's theorem on the interval [−1,1]. cross out

The function f does not satisfy the hypotheses of Rolle's theorem on the interval [−1,1], since f is not continuous at x=0. cross out

The function f does not satisfy the hypotheses of Rolle's theorem on the interval [−1,1], since f is not differentiable at x=0. cross out

The function f does not satisfy the hypotheses of Rolle's theorem on the interval [−1,1], since f(−1)≠f(1).

Solution

Let's analyze each option based on Rolle's Theorem. For a function ff to satisfy Rolle's theorem on a closed interval [a,b][a, b], it must meet three conditions:

  1. Continuity on [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 the function f(x)=xf(x) = |x| on the interval [1,1][-1, 1]:

  1. f(x)f(x) is continuous on [1,1][-1, 1], since absolute value functions are continuous everywhere.
  2. f(x)f(x) is not differentiable at x=0x = 0, as there is a cusp at x=0x = 0.
  3. f(1)=1=1f(-1) = |{-1}| = 1 and f(1)=1=1f(1) = |1| = 1, so f(1)=f(1)f(-1) = f(1).

Since the function fails the differentiability condition (it’s not differentiable at x=0x = 0), the correct answer is:

The function ff does not satisfy the hypotheses of Rolle's theorem on the interval [1,1][-1,1], since ff is not differentiable at x=0x = 0.


Would you like further details or have any questions?

Related Questions

  1. How do we determine if a function is differentiable at a point?
  2. What are other examples of functions that are continuous but not differentiable?
  3. How would the result change if the interval was [0,1][0,1] instead of [1,1][-1,1]?
  4. Why is continuity alone not enough to apply Rolle's Theorem?
  5. Can Rolle's Theorem be applied to functions with endpoints not included in the interval?

Tip

When checking if Rolle's Theorem applies, always verify differentiability over the entire open interval—not just at the endpoints.

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Math Problem Analysis

Mathematical Concepts

Absolute Value
Differentiability
Continuity

Formulas

f(x) = |x|

Theorems

Rolle's Theorem

Suitable Grade Level

Grade 12 / College