FIG. 2
. Equilibria in
for Eq. (9) are plotted vs.
, as in Fig. 1. The direction of increase of time is reversed as compared with Fig. 1; hence,the stable and unstable equilibria are interchanged.
for Eq. (9) are plotted vs. 
, as in
Fig. 1. The direction of increase of time is reversed as compared with Fig. 1; hence,the stable and unstable equilibria are interchanged.