  The article investigates an inverse problem of determining the right-hand
side of a subdiffusion equation with Caputo fractional derivative whose
elliptic part has the most general form and is defined on an N-dimensional
torus T N . The Fourier method is used to prove theorems on the existence and
uniqueness of the classical solution of the initial-boundary value problem and
on the unique reconstruction of the unknown right-hand side of the equation.
Requirements for the initial function and for the additional condition are
established under which the classical Fourier method can be applied to the
inverse problem under consideration.
