Exer. 13.1
Exer. 13.1, another solution
Exer. 13.2
Exer. 13.3
Exer. 13.4
Exer. 13.5
Exer. 13.6
Exer 13.7
Exer. 13.8
Exer. 13.8 another solution
Exer. 13.9
Exer. 13.10
Exer. 13.11
Exer. 13.12
Exer. 13.13
Exer. 13.14
Exer. 13.15
Exer. 13.16
Exer. 13.17
Exer. 13.18
Exer. 13.19
Exer. 13.20
Exer. 13.21
Exer. 13.22
Exer. 13.23
Exer. 13.24
Exer. 13.24 another solution
Exer. 13.25
Exer. 13.26
Exer. 13.27
Exer. 13.28
Exer. 13.29
Exer. 13.30
Exer. 13.31
Exer. 13.32
Exer. 13.32 another solution
Exer. 13.33
Exer. 13.34
Exer. 13.35
Exer. 13.36
Exer. 13.37
Exer. 13.38
Exer. 13.39
Exer. 13.40
Exer. 13.41
Exer. 13.42
Exer. 13.43
Exer. 13.44
Exer. 13.45
Exer. 13.46
Exer. 13.47
Exer. 13.48
Exer. 13.49
Exer. 13.50
Exer. 13.51
Exer. 13.52
Exer. 13.53
Exer. 13.54
Exer. 13.55
Exer. 13.56
Exer. 13.57
Exer. 13.58
Exer. 13.59
Exer. 13.60
Exer. 13.61
Exer. 13.62