Exer. 5.1
Exer. 5.2
Exer. 5.3
Exer. 5.4 two different approaches
Exer. 5.5
Exer. 5.6
Exer. 5.7
Exer. 5.8
Exer. 5.9
Exer. 5.10
Exer. 5.10, another answer
Exer. 5.10, a third answer
Exer. 5.10, another view
Exer. 5.10, another two solutions
Exer. 5.11
Exer. 5.12
Exer. 5.13
Exer. 5.14
Exer. 5.15