(Variation of parameter) Another method of obtaining (4)
Chapter 1, Problem 1.5(choose chapter or problem)
(Variation of parameter) Another method of obtaining (4) results from the following idea. Write (3) as ey*, where y* is the exponential function. which is a solution of the homogeneous linear ODE y*' + py* = O. Replace the arbitrary constant e in (3) with a function II to be determined so that the resulting function y = IIY* is a solution of the nonhomogeneous linear ODE y' + PY = r.
Unfortunately, we don't have that question answered yet. But you can get it answered in just 5 hours by Logging in or Becoming a subscriber.
Becoming a subscriber
Or look for another answer