The research reported in this paper treats three kinds of solution of Dr. Goodwin's nonlinear business cycle model by the three different approaches.
The first case is a graphical solution by applying a new graphical method which is based upon the Prof. Cunningham's contribution. The second case is an analog solution by the Hitachi's low-speed analog computer comparing with Prof. Strotz and others' analog solution by an electrical analog circuit. And, the final case is a digital solution by the transistor automatic digital computer, Mark IV, which has experimentally produced by Electrotechnical Laboratries in Nov, 1957. Its coding is programmed according to the same numerical method based upon our graphical method.
All methods showed in this papar are directly applicable to Dr. Goodwin's mixed difference- differential equation without expanding the difference term into Taylor's series.