Please do Questions 18, 19, 20 and 21.

10. volume of 10 III . Material for the base costs $10 per squal rial for the sides costs $6 per square meter. Find the cost of materials for the cheapest such container. 17. Do Exercise 16 assuming the container has a lid that is made from the same material as the sides. mu 18. (a) Show that of all the rectangles with a given area, the one bloe in with smallest perimeter is a square. (b) Show that of all the rectangles with a given perimeter, the one with greatest area is a square. 19. Find the point on the line y = 2x + 3 that is closest to the origin. unover or 20. Find the point on the curve y = vx that is closest to the point (3, 0). 21. Find the points on the ellipse 4x2 + y = 4 that are farthest away from the point (1, 0). 22. Find, correct to two decimal places, the coordinates of the point on the curve y = sin x that is closest to the point (4, 2). 23. Find the dimensions of the rectangle of largest area that can be inscribed in a circle of radius r. 24. Find the area of the largest rectangle that can be inscribed in