A company that manufactures aluminum cans requires a cylindirical container with a capacity of 500 cubic centimeters (1/2 liter). The top and bottom of the can will be made of special aluminum alloy that costs $0.05 per square centimeter. The sides of teh can are to be made of material that costs $0.02 per square centimeter. Express the cost of the material for the can as a function of the radius r of the can.