1 point) The Nearsighted Cow Problem: A Calculus Classic. A rectangular billboard 8 feet in height stands in a field so that its bottom is 11 feet above the ground, A nearsighted cow with eye level at 4 feet above the ground stands a feet from the billboard. Express d, the vertical angle subtended by the billboard at her eye, in terms of . Then find the distance To the cow must stand from the billboard to maximize 8, #(x) = is maximized when co ( Click on image for a larger view )