Chapter VIII. Linear equations of second order. Excercise VIII (C) at page 133

83.38.1 problem 1
83.38.2 problem 2
83.38.3 problem 3
83.38.4 problem 4
83.38.5 problem 5
83.38.6 problem 6
83.38.7 problem 7
83.38.8 problem 8
83.38.9 problem 9