More textbooks are talking about qualitative methods and the use of nullclines in the analysis of differential systems. To facilitate this, PPLANE5 now has the capability of plotting the nullclines for a planar system.

The display of nullclines can be initiated in two ways. If it is initiated in the Setup Window, there results the nulclines with only a few direction field arrows as we see here:

On the other hand, if it is initiated from the Solutions menu in the Display Window, the nullclines are superimposed on the vector field as in this example:

John C. Polking <>
Last modified: Fri Jan 28 14:53:54 CST 2000