56.36 Chapter IX, Miscellaneous methods for solving equations of higher order than first. Article 60. Exact equation. Integrating factor. Page 139

56.36.1 problem Ex 1
56.36.2 problem Ex 2
56.36.3 problem Ex 3
56.36.4 problem Ex 4
56.36.5 problem Ex 5
56.36.6 problem Ex 6
56.36.7 problem Ex 7
56.36.8 problem Ex 8
56.36.9 problem Ex 10