Statement of border tasks on the plane dependent on the coefficients for the type of the wave equation. I

In the half-strip we consider problems for a second-order equation with constant coefficients, whose operator represents a composition of first-order operators. The Cauchy and Dirichlet conditions join the equation. One of the coefficients of the equation as a parameter varies with respect to another quantity, sign. Depending on this, the correct problems for the simplest boundary conditions are considered.