  A numerical explicit method to evaluates transient solutions of linear
partial differential inhomogeneous equation with constant coefficients is
proposed. A general form of the scheme for a specific linear inhomogeneous
equation is shown. The method is applied to the wave equation and the diffuse
equation and is investigated by simulating simple models. The numerical
solutions of the proposed method show good agreement to the exact solutions.
Comparing with explicit FDM, FDM shows the instability by the violation of CFL
condition whereas the proposed method is always stable irrespective of any time
step width.
