COMMENTS ON HOMEWORK 3
    
1. This was much better than homework 2!  There is still lots
   of room for improvement (the drill sergeant never stops yelling).
   
2. If there is something you don't understand, find out.  This applies
   particularly to Matlab programming.  There are plenty of people
   in the class who can do it, find one of them.
   
3. Make sure you label each graph.  You can just write something in
   or use the computer.
   
4. Don't switch off the brain.  The majority of the class correctly
   found the eigenvalues for question 3.  EVERY one of you said that
   the system should be stable because the eigenvalues have negative
   real part.  NOT ONE of you commented that the computed solution
   does something else: it grows.