27 Chapter 2, Second-Order Differential Equations. section 2.1.2-1 Equation of form \(y''+f(x)y'+g(x)y=0\)

 27.1 problem 11
 27.2 problem 12
 27.3 problem 13
 27.4 problem 14
 27.5 problem 15
 27.6 problem 16
 27.7 problem 17
 27.8 problem 18
 27.9 problem 19
 27.10 problem 20
 27.11 problem 21
 27.12 problem 22
 27.13 problem 23
 27.14 problem 24
 27.15 problem 25
 27.16 problem 26