HOMEWORK 4:

  * This homework assignment is due Friday, June 12.

  POLICY: Homework solutions should be written up in a proper 
  and coherent fashion. It is OK to discuss homework with
  other students or dr.G. Please achknowledge any help received. 
  
  (1) [10 pts] [#9, p.72]

  (2) [10 pts] [#13, 14, 15, p.73]
 
  (3) [15 pts] [#1, p.91]