Problem 7. Schaefer model: suppose that the yield (harvest h) is given by h = 2Ex , where E is the amount of fishing effort and x is population (here q, the productivity parameter, equals 2). a. Find sustainable population x as a function of effort E. b. Find sustainable yield as a function of E. c. Graph the resulting Yield-Effort curve. Which portions of this curve correspond to biological overfishing?Problem 6. Logistic population growth: suppose the growth rate of a population of wild fish is given by F(x) = 10x - 0.01x- if the population is left undisturbed, were x is population. a. What is the equilibrium natural population? b. What is the maximum sustained yield, and the corresponding population? c. Graph the population growth function. Which portions of this function correspond to biological overfishing?Problem 4. Use the Kuhn-Tucker conditions to find maxima for the following: a. F(x, y) = xy, subject to (i) x- + y