8.8 Chapter 2. Second order differential equations. Section 2.2.1 Linear equations with constant coefficients (complex roots). Excercises page 144

8.8.1 problem 1
8.8.2 problem 2
8.8.3 problem 3
8.8.4 problem 4
8.8.5 problem 5
8.8.6 problem 6
8.8.7 problem 8
8.8.8 problem 9
8.8.9 problem 11
8.8.10 problem 18
8.8.11 problem 19