Consider the Following Nonlinear System Expressed in Polar Form

Multiple Choice

Consider the following nonlinear system expressed in polar form: = r ( r - 7)
= -1
Which of these statements is true? Select all that apply.

A) All solution trajectories approach either r = 5 or r = 7 in a counterclockwise fashion.
B) r = 5 is a semistable limit cycle.
C) r = 7 is an unstable limit cycle.
D) For 0 < r < 5, the corresponding solution trajectories spiral toward r = 5 in a clockwise fashion.
E) For r > 7, the corresponding solution trajectories spiral outward away from r = 7 in a counterclockwise fashion.