Q. Let h(x)=∣x∣.Can we use the mean value theorem to say the equation h′(x)=0 has a solution where −1<x<1 ?Choose 1 answer:(A) No, since the function is not differentiable on that interval.(B) No, since the average rate of change of h over the interval −1≤x≤1 isn't equal to 0 .(C) Yes, both conditions for using the mean value theorem have been met.
Mean Value Theorem: The Mean Value Theorem states that if a function f is continuous on the closed interval [a,b] and differentiable on the open interval (a,b), then there exists at least one c in the interval (a,b) such that f′(c) is equal to the average rate of change of the function over [a,b]. We need to check if h(x)=∣x∣ satisfies these conditions on the interval [−1,1].
Continuity Check: First, we check for continuity. The function h(x)=∣x∣ is continuous on the entire real line, including the closed interval [−1,1]. Therefore, the first condition of the Mean Value Theorem is satisfied.
Differentiability Check: Next, we check for differentiability. The function h(x)=∣x∣ is differentiable everywhere except at x=0, because the absolute value function has a sharp corner at that point. Since 0 is within the open interval (−1,1), the function h(x) is not differentiable on the entire interval (−1,1). Therefore, the second condition of the Mean Value Theorem is not satisfied.
Conclusion: Since h(x) is not differentiable on the entire interval (−1,1), we cannot apply the Mean Value Theorem to assert that there exists a c in (−1,1) such that h′(c)=0. The correct answer is (A) No, since the function is not differentiable on that interval.
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