Inverse problems for the second order hyperbolic equation with unknown time depended coefficient

We analyze the solvability of the inverse problem with an unknown time depended coefficient for a second-order hyperbolic equation. We also study uniqueness of the problem solution. The problem is stated as follows: it is required to find a solution and an unknown coefficient of the equation. Here the problem is considered in a rectangle area, with a set conditions being typical of the first boundary-value problem and an overdetermination condition being necessary of the unknown coefficient searching. To study solvability of the inverse problem, we realize a conversion from the initial problem to a some direct supplementary problem with trivial boundary conditions. We prove the solvability of the supplementary problem in the class of the functions considered above. Then we realize a conversion to the first problem again and as a result we receive the solvability of the inverse problem. To prove solvability of the problem, we use the method of continuation on a parameter, fixed point theorem, cut-off functions, and the method of regularization. In the article we prove the theorems of the existence and the uniqueness of the problem solution in the class of the functions considered above.