PHASE-PLANE METHODS.

The phase-plane method is a graphical method for linear and nonlinear second-order systems. There are many techniques for obtaining the phase portrait which consists of a number of phase trajectories on the phase plane. From the summary and discussion the isocline method is a most general and useful method. The only difficulty is in the labor required. Solution by digital computer reduces this difficulty and makes the isocline method a much more useful method in non-linear systems analysis and design applications. Author