72.11 Chapter 3. Second order linear equations. Section 16. The Use of a Known Solution to find Another. Problems at page 121

72.11.1 problem 2 (a)
72.11.2 problem 2 (b)
72.11.3 problem 3
72.11.4 problem 4
72.11.5 problem 5
72.11.6 problem 6
72.11.7 problem 7 (a)
72.11.8 problem 7 (b)
72.11.9 problem 7 (c)
72.11.10 problem 8
72.11.11 problem 9
72.11.12 problem 10 (a)
72.11.13 problem 10 (b, n=1)
72.11.14 problem 10 (b, n=2)
72.11.15 problem 10 (c, n=3)
72.11.16 problem 11