11.1 Chapter 4.1, Higher order linear differential equations. General theory. page 173

11.1.1 problem 1
11.1.2 problem 2
11.1.3 problem 8
11.1.4 problem 9
11.1.5 problem 10
11.1.6 problem 11
11.1.7 problem 16
11.1.8 problem 17
11.1.9 problem 20
11.1.10 problem 21