Toronto Math Forum

MAT244-2014F => MAT244 Math--Tests => Quiz 4 => Topic started by: Yuan Bian on November 12, 2014, 09:03:38 PM

Title: Q4 problem 2
Post by: Yuan Bian on November 12, 2014, 09:03:38 PM
Q2: 7.6 #6
r2+9=0
r1=3i, r2=-3i
pure imaginary eigenvalue, so it's stable center
also whole soln is in the q1 fisrt post.
Title: Re: Q4
Post by: Guang_Yang on November 12, 2014, 09:53:49 PM
7.6 #6
Title: Re: Q4 problem 2
Post by: Tao Hu on November 13, 2014, 03:36:44 PM
How to determine the direction of the circular phase portrait? What is the difference between clockwise and anti-clockwise?    :o
Title: Re: Q4 problem 2
Post by: Yuan Bian on November 13, 2014, 09:13:45 PM
from prof Victor Ivrii : "Why you just don't learn a very simple criteria for the center or focus: if the top-right element of 2×2 matrix is >0 the orientation is clock-wise; otherwise it is counter-clock-wise."
Title: Re: Q4 problem 2
Post by: Shuyang Wang on November 13, 2014, 09:52:56 PM
Just a plot by software