8. (Obj. 9) You are designing a rectangular poster to contain 50 in of printing with a 4-in margin at the top and bottom and a 2-in margin at each side. (a) (5 points) Draw a diagram to represent the problem? (b) (11 points) What overall dimensions will minimize the amount of paper used?11. (8 points) (Obj. 14) Find the area under the curve of f(x) = x - Vx on the interval [1,4].13. (10 points) (Obj. 16) An iron ball of 8 inches in diameter is coated with a layer of ice of uniform thickness. If the ice melts at a rate of 10 in' /min, how fast is the thickness of the ice decreasing when it is 2 inches thick