The Harrod–Domar model of the growth of an economy is based on three assumptions. (1) Savings, St, in any time period are proportional to income, Yt, in that period, so that
St = aYt (a > 0)
(2) Investment, It, in any time period is proportional to the change in income from the previous period to the current period so that
It = b(Yt − Yt-1) (b > 0)
(3) Investment and savings are equal in any period so that
It = St
Use these assumptions to show thatand hence write down a formula for Yt in terms of Y0. Comment on the stability of the system in the case when a = 0.1 and B = 1.4.