This article describes three approximation methods I used to solve the growth model (Model 1) studied by the National Bureau of Economic Research's nonlinear rational-expectations-modeling group ...

Even for ρ1 and ρ2 as small as 2, the expansion is unwieldy. We shall show that as ρ1 and ρ2 → ∞, the probability function of z approaches a normal curve and in case r = 0 the Type III function and ...