A fenced enclosure consists of a rectangle of length L and width 2R, and a semicircle of radius R, as shown in Figure P20. The enclosure is to be built to have an area A of 1600 ft^2. The cost of the fence is $40/ft for the curved portion and $30/ft for the straight sides. Use the min function to determine with a resolution of 0.01 ft the value of R and L required to minimize the total cost of the fence. Also compute the minimum cost.