75.13 Chapter 2 (Higher order ODEs). Section 13. Basic concepts and definitions. Exercises page 98

75.13.1 problem 318
75.13.2 problem 319
75.13.3 problem 320
75.13.4 problem 321
75.13.5 problem 322
75.13.6 problem 323
75.13.7 problem 324
75.13.8 problem 325
75.13.9 problem 326