The piecewise function h is defined as follows: h(x) = cases 5x+2, & x < 3

MATHEMATICS · Multi-part · AP · Calculus AB · Differentiation: Definition and Fundamental Properties · Differentiation: Definition and Fundamental Properties

Problem

The piecewise function h is defined as follows: h(x)={5x+2,x<3,x2−4x+k,x≥3,h(x) = \begin{cases} 5x+2, & x < 3,\\ x^2 - 4x + k, & x \ge 3, \end{cases} where k is a real constant. Answer the questions that follow. (a) Determine the value of k for which h is differentiable at x = 3. Justify your answer by evaluating appropriate limits. (b) For the k found in part (a), compute h′(3). Show all limit manipulations. (c) Describe geometrically how your work in parts (a) and (b) ensures that the two pieces of h connect to form a single smooth curve at x = 3.

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