4.5. PERIOD-5 AND PERIOD-6 MOTIONS TO CHAOS 27
2:1696, another saddle-node bifurcation occurs, where the symmetric period-4 motions
switches from stable to unstable, and asymmetric period-4 motions are introduced. Again, such
asymmetric period-4 motions are not illustrated herein. On the third bifurcation tree, the in-
dependent symmetric period-4 motion is stable for 2 .2:2013; 2:2543/, which overlay with
part of the second bifurcation tree. At 2:2543, a saddle-node bifurcation is for the onset
of symmetric period-4 motion with a stable to unstable switching. At 2:2013, the saddle-
node bifurcation introduces asymmetric period-4 motions while the symmetric period-4 mo-
tions become unstable. A more detailed presentation is provided through the zoomed view for
2 .2:0; 3:0/ in Figs. 4.5c,d. e aforementioned three bifurcation trees of period-4 motions
to chaos are non-travelable. However, the fourth branch of asymmetric period-4 motions to
chaos is travelable for 2 .0:0;5:8029/. e onset of such asymmetric period-4 motions occurs
at 5:8029, and the stable asymmetric period-4 motions exist for 2 .5:5327; 5:8029/. At
5:5237, the period-doubling bifurcation of the asymmetric period-4 motion occurs for the
asymmetric period-8 motion, which will not be presented herein.
4.5 PERIOD-5 AND PERIOD-6 MOTIONS TO CHAOS
e bifurcation trees for travelable asymmetric period-5 motions to chaos are presented in
Figs. 4.6a,b for 2 .2:0; 6:5/. ere are two bifurcation trees of period-5 motions to chaos. e
paired period-5 motions are asymmetric. On the first bifurcation tree, the asymmetric period-5
motion is stable for 2 .6:0804; 6:1537/. e onset of such asymmetric period-5 motions is at
the saddle-node bifurcation of 6:1537. At 6:0804, period-doubling bifurcation of the
asymmetric period-5 motion introduces period-10, period-20… motions which are not illus-
trated due to the tiny stable ranges. On the second bifurcation tree, the asymmetric period-5
motions exist for 2 .3:9425; 3:9625/. e saddle-node bifurcation of 3:9625 is for the
onset of the asymmetric period-5 motion. At 3:9425, the cascaded period-doubling bifur-
cation of the asymmetric period-5 motion introduces period-10, period-20… motions eventu-
ally to chaos.
e tree bifurcation trees for independent period-6 motions are presented in Figs. 4.6c,d
for 2 .3:2; 4:4/. Such period-6 motions are independent, which are not born from period-
doubling bifurcations of period-3 motions. Two kinds of bifurcation trees of period-6 motion to
chaos are observed. e first kind of bifurcation tree is from symmetric to asymmetric period-6
motions and to chaos, which is non-travelable. e second kind of bifurcation tree is directly
from an asymmetric period-6 motion to chaos, which is travelable. ere is only one bifurca-
tion tree for independent asymmetric period-6 motions to chaos. Such an asymmetric period-
6 motion is stable for 2 .3:7261; 3:7363/, which are neither from saddle-node bifurcations
of symmetric period-6 motion, nor from period-doubling bifurcations of asymmetric period-3
motions. Instead, such a bifurcation tree of the asymmetric period-6 motion to chaos exist in-
dependently. At 3:7363, saddle-node bifurcation is for onset of the asymmetric period-6
motion. At 3:7261, such an asymmetric period-6 motion is from stable to unstable through