8.25 Section 3.12, Systems of differential equations. The nonhomogeneous equation. variation of parameters. Page 366

8.25.1 problem Example 1, page 361
8.25.2 problem Example 2, page 364
8.25.3 problem 1
8.25.4 problem 2
8.25.5 problem 3
8.25.6 problem 4
8.25.7 problem 5
8.25.8 problem 6
8.25.9 problem 10
8.25.10 problem 11
8.25.11 problem 12
8.25.12 problem 13
8.25.13 problem 14
8.25.14 problem 16
8.25.15 problem 17
8.25.16 problem 18