In Exercises 59 and $60,$ give reasons for your answers.
Let
$$
f(x)=(x-2)^{2 / 3}
$$
$$
\begin{array}{l}{\text { a. Does } f^{\prime}(2) \text { exist? }} \\ {\text { b. Show that the only local extreme value of } f \text { occurs at } x=2 \text { . }} \\ {\text { c. Does the result in part (b) contradict the Extreme Value }} \\ {\text { Theorem? }} \\ {\text { d. Repeat parts (a) and (b) for } f(x)=(x-a)^{2 / 3}, \text { replacing } 2 \text { by } a \text { . }}\end{array}
$$