(20 points) Suppose you own a stand of fast-growing pines. The growth function of the pines is Q(t) = 10t+t2 -0.01t3, where Q(t) is the volume of timber in year t. a) What is the maximum volume of timber this stand of pines can produce? (5 points) b) Suppose the difference between the timber price and the harvesting cost is $1, the replanting cost is $150, and the discount rate is 5%. Please find out the optimal rotation interval T*, the volume of timber at T*. (15 points)