(1 point) The Nearsighted Cow Problem: A Calculus Classic. A rectangular billboard 5 feet in height stands in a field so that its bottom is 9 feet above the ground. A nearsighted cow with eye level at 4 feet above the ground stands a feet from the billboard. Express 0, the vertical angle subtended by the billboard at her eye, in terms of x. Then find the distance , the cow must stand from the billboard to maximize 0. 0(x) = is maximized when co Senighed Cow Problem (Click on image for a larger view )