30 Chapter VIII, Linear differential equations of the second order. Article 53. Change of dependent variable. Page 125

  30.1 problem Ex 1
  30.2 problem Ex 2
  30.3 problem Ex 3
  30.4 problem Ex 4
  30.5 problem Ex 5
  30.6 problem Ex 6
  30.7 problem Ex 7
  30.8 problem Ex 8