11: A farmer wishes to construct a rectangular storage bin with a volume of 1000 cubic feet. Both the top and the bottom of the bin are to be squares. Find the dimensions of the bin which will minimize its surface area. 13. Suppose the material for the top and the bottom of the bin in Problem 11 costs $2.00 per square foot while the material for the sides costs $3.00 per square foot. Find the dimensions of the bin which minimize its cost.