679602.fig.004a
(a)
679602.fig.004b
(b)
679602.fig.004c
(c)
679602.fig.004d
(d)
Figure 4: Trajectory portrait and phase portrait of system (57) with , . The positive equilibrium (5.61, 7.02) is asymptotically stable. The initial value is (5.6, 7.45).