Let on the closed interval .

MATHEMATICS · Multi-part · A Level · Mathematics · Differentiation · Differentiation

Problem

Let g(x)=∣x2−4x∣g(x)=|x^{2}-4x| on the closed interval [−1,5][-1,5]. (a) Rewrite gg as an explicit piecewise–defined function without the absolute value symbol, clearly indicating the interval on which each branch is valid. (b) Determine every point in (−1,5)(-1,5) where gg fails to be differentiable. Show all reasoning, including derivative calculations or limits from each side as appropriate. (c) Decide whether the hypotheses of the Mean Value Theorem are met on [−1,5][-1,5]. Provide a logical argument that references your work in parts (a) and (b). (d) If you concluded in part (c) that the hypotheses are satisfied on any subinterval of [−1,5][-1,5], select one such subinterval and find at least one value cc in the interior of that subinterval for which g′(c)g'(c) equals the average rate of change of gg over that subinterval. Show all supporting calculations.

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