Abstract: According to Mikusinski's fundamental view, we reconstruct a direct method of operation a calbulus which may be adapted to search for the solution of differential equations with variable coefficients.
The present paper is devoted to solutions of two types——indirect (undetermined) method and direct (series of integral) method-for solving second-order linear differential equations:The latter displays forthright feature while the former can solve second-order linear differential equation and interrelate first-order Riccati's non-linear differential equation at the same time.