What are some of the factors that could make social user costs different from private user costs in the case of mineral extraction? a. Graphically and mathematically illustrate how, in a two period model of a nonrenewable resource, economic efficiency in the presence of a positive rate of discount implies increased consumption today and higher prices and lower consumption tomorrow than would be observed with a discount rate of zero. b. Graphically and mathematically illustrate how user cost is affected by the expectation that future demand for a resource will shift outward on today’s efficient rate of extraction