Assume that K * is the firm's desired capital stock and assume that it is xed. It is costly to adjust the capital stock, so the firm adjusts gradually towards K *. The change in the capital stock is proportional to the gap between the desired capital stock and the current capital stock, where a is the factor of proportionality that determines the speed of adjustment. Assuming there is no depreciation, and assuming that the initial capital stock at t = 0 is given by K0, Write out the differential equation for the capital stock and solve it