An incompressible fluid is contained between two infinite parallel plates. Under the influence of a harmonically varying pressure gradient in the x direction, the fluid oscillates harmonically with a frequency $.$ The differential equation describing the fluid motion is where X is the amplitude of the pressure gradient. $(1)(10$ pt$)$ Express this equation in dimensionless form using h and as reference parameters. Make u$,$ y$,$ and t dimensionless using h and $,$ but keep X in the procedure of non dimensionalization. $(2)(5$ pt$)$ In the dimensionless equation, find the dimensionless expression for X in terms of $,$ h$,$ and $.$