Toronto Math Forum
MAT2442014F => MAT244 MathTests => Quiz 4 => Topic started by: Yuan Bian on November 12, 2014, 09:03:38 PM

Q2: 7.6 #6
r^{2}+9=0
r_{1}=3i, r2=3i
pure imaginary eigenvalue, so it's stable center
also whole soln is in the q1 fisrt post.

7.6 #6

How to determine the direction of the circular phase portrait? What is the difference between clockwise and anticlockwise? :o

from prof Victor Ivrii : "Why you just don't learn a very simple criteria for the center or focus: if the topright element of 2Ã—2 matrix is >0 the orientation is clockwise; otherwise it is counterclockwise."

Just a plot by software