Coefficient Inverse Problem for an Equation of Mixed Parabolic-Hyperbolic Type with a Noncharacteristic Line of Type Change

In this paper, the direct and two inverse problems for a model equation of mixed parabolic-hyperbolic type are studied. In the direct problem, the Tricomi problem for this equation with a noncharacteristic line of type change is considered. The unknown of the inverse problem is the variable coefficient at the lowest derivative in the parabolic equation. To determine it, two inverse problems are studied: with respect to the solution defined in the parabolic part of the domain, the integral overdetermination condition (inverse problem 1) and one simple observation at a fixed point (inverse problem 2) are given. Theorems on the unique solvability of the formulated problems in the sense of a classical solution are proved.