18) The graph below shows the first derivative of a function y = f(x). Select a possible graph for f(x). SHORT ANSWER. Show all work to receive partial credit. Solve the problem. 19) A company is constructing an open-top, square-based, rectangular metal tank that will have a volume of 46.5 fts. What dimensions yield the minimum surface area? Round to the nearest tenth, if necessary. A) B) MULTIPLE CHOICE. Choose the one alternative that best answers the question. 20) A rectangular sheet of perimeter 27 cm and dimensions x cm by y cm is to be rolled into a cylinder as shown in part (a) of the figure. What values of x and y give the largest volume? circumference = x D) A) x = 8 cm: y = - cm B) x = 9 cm; y = = cm C) x = 11 cm: y = 7 cm D) x = 10 cm: y = > cm