12.1 problem 1
12.2 problem 2
12.3 problem 3
12.4 problem 4
12.5 problem 5
12.6 problem 6
12.7 problem 7
12.8 problem 8
12.9 problem 9
12.10 problem 10
12.11 problem 11
12.12 problem 12
12.13 problem 13
12.14 problem 14
12.15 problem 15
12.16 problem 16
12.17 problem 17
12.18 problem 18
12.19 problem 19
12.20 problem 20
12.21 problem 21
12.22 problem 22
12.23 problem 23
12.24 problem 24
12.25 problem 25
12.26 problem 26
12.27 problem 27
12.28 problem 28
12.29 problem 29
12.30 problem 30
12.31 problem 31
12.32 problem 32
12.33 problem 33
12.34 problem 34
12.35 problem 35
12.36 problem 36
12.37 problem 37
12.38 problem 38
12.39 problem 39
12.40 problem 40
12.41 problem 41
12.42 problem 42
12.43 problem 43
12.44 problem 44
12.45 problem 45
12.46 problem 46
12.47 problem 55
12.48 problem 56
12.49 problem 57
12.50 problem 58 (a)
12.51 problem 59
12.52 problem 60
12.53 problem 61
12.54 problem 61 (a)
12.55 problem 62
12.56 problem 62 (a)
12.57 problem 63
12.58 problem 63 (b)
12.59 problem 63 (c)
12.60 problem 64
12.61 problem 65