14.18 Chapter 9, First order linear systems. Section 9.6 (Variation of parameters for linear systems), page 624

14.18.1 problem 1
14.18.2 problem 2
14.18.3 problem 3
14.18.4 problem 4
14.18.5 problem 5
14.18.6 problem 6
14.18.7 problem 7
14.18.8 problem 8
14.18.9 problem 9
14.18.10 problem 11