A farmer has two miles of fence, and wants to enclose the max possible area for his cows. He will use fence on only three sides because the fourth side is a river that flows through his land. The path of the river is the parabola y=4-x^2. One of the ends of the fence is on the vertex of the parabola. and the other end of the fence is on the parabola somewhere in the first quadrant. Find the exact value of the max area. Here an image of how i labeled the variables on the graph and the two equations I got: http://img139.imageshack.us/img139/1655/problemnl2.png [Broken] 2 = t + 2s - a The professor only told us to label that point (s,t) and that we'd have to differentiate the integral eventually. I'm confused about which letters should be treated as variables because I know I have to work with the perimeter equation to substitute it in. Any helpful hints or nudges in a good direction?