An analysis of the periodicity, convergence and boundedness of the solutions of the second order difference equation in the title is presented. The parameters , , , and the initial conditions and are nonnegative and the denominator is always positive. The main result is the following.
Theorem 1. (a) Assume that Then every solution of the given equation converges to a period two solution. (b) If , then the equation possesses unbounded solutions. (c) If then every solution of the equation has a finite limit.
In the case (b), the difference equation has a positive equilibrium which is a saddle point. In case (c), the equation may possess a unique equilibrium (zero or positive) which is globally asymptotically stable, or two equilibrium points of which one is zero (and this is unstable) and the other is positive (locally asymptotically stable).