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

5.1.1 problem 1
5.1.2 problem 2
5.1.3 problem 8
5.1.4 problem 9
5.1.5 problem 10
5.1.6 problem 11
5.1.7 problem 16
5.1.8 problem 17
5.1.9 problem 20
5.1.10 problem 21