4. For each of the following difference equations, determine the equilibrium points. Then, use the specified method to determine whether each equilibrium point is stable or unstable. a. AP =0.7 P ; Method to determine stability: algebraic perturbation analysis b. AP = 2 P(1 - P/15) ; Method to determine stability: calculus C. P.1 = 2 P. (1-P./4) ; Method to determine stability: cobweb diagram ----- P(t+1) = P(t) - - P(t+1) = 2*P(t)*(1-P(t)/4) 3.5 3 Population at time t+1 2.5 N 1.5 0.5 0 0.5 1.5 2 2.5 3 3.5 Population at time t