66. For the following exercises, use the graph of y = f(x) to sketch the graph of its derivative f'(x). 16- 12- at -10 1 3 -4 -8- -12 16 71. For the following exercises, the given limit represents the derivative of a function y = f(x) at x=a. Find f(x) and a. lim h-o (2+4)4-16 h