Consider a water heater manufacturing company. The number of water heaters manufactured per day, q, is a function of the number of workers per day, L, and the number of square feet of sheet metal per day, S. Specifically, its (general) CES production function is -2 -0.5 2 S q= + 40 The wage is $320, and the price per square foot of sheet metal is $8.00. What is the marginal productivity of labor? The marginal product of labor (MPL) is MPL = (Properly format your expression using the tools in the palette. Hover over tools to see keyboard shortcuts. E.g., a superscript can be created with the ^ character.)