87.3 Chapter 1. Elementary methods. First order differential equations. Exercise at page 26

87.3.1 problem 1
87.3.2 problem 2
87.3.3 problem 3
87.3.4 problem 4
87.3.5 problem 5
87.3.6 problem 6
87.3.7 problem 7
87.3.8 problem 8
87.3.9 problem 9
87.3.10 problem 10
87.3.11 problem 11
87.3.12 problem 12
87.3.13 problem 13
87.3.14 problem 14
87.3.15 problem 17
87.3.16 problem 20
87.3.17 problem 21