7. A cylindrical can is to be made to hold 2000cm' (one litre) of oil. Find the dimensions (radius and height) of the can that will minimize the cost of the metal to make the can. (The minimum cost corresponds to a minimum of the total area of the can (cylinder)). (6 Marks) 8. Determine the second derivative of each of the following functions: a. h(x) = 3x4 - 4x3- 3x2-5 b. f (x) = (2x - 5)3 15 c. y = x+3 d. g(x) = Vx2 +1 (8 marks)