Application of the finite integral transform method to solving a mixed problem with integro-differential conditions for a nonclassical equation

We consider a mixed problem with integro-differential boundary conditions for a nonclassical equation. Under certain conditions, we apply a finite integral transform to this problem and obtain a parametric problem. We introduce the notion of proper boundary conditions of the parametric problem, which is wider than the notion of regularity. By applying the inverse integral transform to the solution of the parametric problem, we obtain an analytic representation of the solution of the original mixed problem.