# Asymptotic stability of a system ( ordinary DE)

1. Dec 7, 2005

### ODEMath

Determine the asymptotic stability of the system x' = Ax where

A is 3 x 3 matrix

A = -1 1 1
0 0 1
0 0 -2

( first row is -1 1 1 second is 0 0 1 and third is 0 0 -2)

More specifically, what stability conclusion(s) can be drawn? ( Justify your answer)

2. Dec 7, 2005

### D H

Staff Emeritus
The solution of this system is
$$x(t) = exp(At) x(t=0)$$
Try evaluating
$$exp(At) = \sum_n \frac{t^n}{n!}A^n$$

3. Dec 8, 2005

### saltydog

I think analyzing this system qualitatively along the lines presented in "Differential Equations" by Blanchard, Devaney, and Hall (other books too) is a nice way of drawing conclusions about this and other systems. Try it.

Of course, first do a few 2-D ones.

4. Dec 8, 2005

### HallsofIvy

Staff Emeritus
Have you determined the eigenvalues of that matrix?