Variation in θ = δΣ/Σ, the ratio of the perturbed surface density to the unperturbed surface density, with τ, dimensionless time in the sheared frame, plotted for three different β values, and for Q = 1.1, X = 1, η = 1, for a one-fluid case. As seen clearly, with the increase of the disk thickness, the resulting MAF of the solution decreases steadily. The net amplitude αθ ≪ 1 at all τ, where α is a scale factor.