Classical solution of the first mixed problem for a third-order hyperbolic equation with the wave operator

We study the classical solution of the boundary value problem for a third-order hyperbolic equation defined on the plane in a half-strip with the Cauchy conditions on the lower base of the domain and with the Dirichlet conditions on the lateral boundary. By the method of characteristics, in the case of two independent variables, we find the solution of the problem in closed form and prove its uniqueness.