December 2020
Intermediate to advanced
1064 pages
49h 43m
English
It was pointed out in the Remarks at the end of Section 3.4 that the method of undetermined coefficients has an inherent weakness that limits its wider application to linear equations: The DE must have constant coefficients, and the input function g(x) must be of the type listed in Table 3.4.1. In this section we examine a method for determining a particular solution yp of a nonhomogeneous linear DE that has, in theory, no such restrictions on it. This method, due to the eminent Italian astronomer and mathematician Joseph-Louis Lagrange (1736–1813), is known as variation of parameters.