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. PHI = 2 P, (1-P/4) ; Method to determine stability: cobweb diagram ----" P(t+1) = P(1) - - P(t+1) = 2"P(1)"(1-P(1)/4) 3.5 3 2.5 N Population at time t+1 1.5 0.5 0.5 1.5 2 2.5 3 3.5 Population at time t 5. Complete the following statements by filling in the blanks: a. The models PA/ = P, and AP = r P, represent growing populations when k is any number in the range and when r is any number in the range b. The models P#1 = KP, and AP = r P, represent unchanging populations when k is any number in the range and when r is any number in the range c. The models PA/ = AP, and AP = r P, represent declining populations when k is any number in the range and when / is any number in the range