This paper considers an n firms oligopoly model with isoelastic demand function and linear cost function. The reaction functions of these firms are determined from these functions, and a dynamical system with naive adaptive process is produced. The equilibrium of this n dimensional system is obtained. In the case of homogeneous firms, the equilibrium becomes unstable when the number of firms is five. By introducing heterogeneity into the five firms' model, the equilibrium becomes stable and there is a path connecting the stable and unstable equilibrium.
