64.3 Chapter 2, section 2.1 (Exact differential equations and integrating factors). Exercises page 37

64.3.1 problem 1
64.3.2 problem 2
64.3.3 problem 3
64.3.4 problem 4
64.3.5 problem 5
64.3.6 problem 7
64.3.7 problem 8
64.3.8 problem 9
64.3.9 problem 10
64.3.10 problem 11
64.3.11 problem 12
64.3.12 problem 13
64.3.13 problem 14
64.3.14 problem 15
64.3.15 problem 16
64.3.16 problem 21
64.3.17 problem 22
64.3.18 problem 24