The differential equation in Example 3 of Section 2.1 is a well-known population model. Suppose the DE is changed to dP = P(aP - b), dt where a andb are positive constants. Discuss what happens to the population P as time t increases. as t increases. If Po > b/a, then P(t) as t increases; if 0 < Po < b/a, then P(t) -? Consider the following autonomous first-order differential equation. + 2) = y In(y + Find the critical points and phase portrait of the given differential equation. oF OF 0F -1-