"4. Proportional Harvesting Model In the proportional harvesting model, the amount of fish a fisherman can take is proportional to P, the population present. Thus only a fraction of the fish are allowed to be harvested every year. If the constant of proportionality is α, where 0 ≤ α ≤ 1, then we can write, dP dt = rP 1 − P K − αP h > 0. (4) (a) Compute the critical points of the proportional harvesting model in equation (4) and use a phase line analysis to classify their stability. You can let r = 1 and keep k = 1200."