In this paper we present an algorithm for finding a “closed-form” solution of the differential equation y″ + ay′ + by, where a and b are rational functions of a complex variable x, provided a “closed-form” solution exists. The algorithm is so arranged that if no solution is found, then no solution can exist. © 1986, Academic Press Inc. (London) Ltd. All rights reserved.
Kovacic, J. J. (1986). An algorithm for solving second order linear homogeneous differential equations. Journal of Symbolic Computation, 2(1), 3–43. https://doi.org/10.1016/S0747-7171(86)80010-4