Software for closed-form solutions of linear time-invariant differential systems

Software that obtains the closed-form solution for first-order linear time-invariant systems with exponential and/or sinusoidal excitations is described. The approach is based on using EIGRF (an IMSL library subroutine, which uses the Q/R algorithm for an arbitrary real input matrix) for determining the eigenvalues and eigenvectors of the coefficient matrix. The closed-form solutions is then obtained by making use of the eigenvalues, the eigenvectors, and the input functions in the variation of parameters formula.