Math 224-01: Differential Equations: Reading Homework 7.7

1. Orbital Portraits : what is true of orbital portraits for two by two systems? what do we do in this section?
   
   1. the Gallery : what are the six categories of orbital portraits for a planar system?
      
      1. Point : what is an eigenline?
         
      2. Point : how does the sign of the eigenvalue determine motion near the eigenline?
         
   2. Sensitivity : how can orbits change with small changes in the matrix entries in a system?