HW4 (due 2/28)
 Section 4.1 (6pts each)
 13, 34, 38, 40, 53

 Section 4.2 (6 pts except #15 is 8pts)
 10, 13, 15, 23

 Section 4.3 #9&11 are 6pts, #17&22 are 8pts)
 9, 11, 17, 22

 Section 4.4 (8pts each)
 2, 5