Chapter 3: Derivatives - Section 3.2 - The Derivative as a Function - Exercises 3.2 - Page 117: 45

a. all the points except $x=0$. b. no points. c. $(0,0)$

a. Examine the graph given by the Exercise; we can find that all the points except $x=0$ in the interval of the function are differentiable. b. Examine the graph given by the Exercise; we can find that no points in the interval of the function are continuous but not differentiable. c. Examine the graph given by the Exercise; we can find that one point at $(0,0)$ in the interval of the function is neither continuous nor differentiable. This is because there is a gap at the origin and the left and right side function limits are not equal (non-removable discontinuity).