4 Chapter 8, Ordinary differential equations. Section 4. OTHER METHODS FOR FIRST-ORDER EQUATIONS. page 406

 4.1 problem 1
 4.2 problem 2
 4.3 problem 3
 4.4 problem 4
 4.5 problem 5
 4.6 problem 6
 4.7 problem 7
 4.8 problem 8
 4.9 problem 9
 4.10 problem 10
 4.11 problem 11
 4.12 problem 12
 4.13 problem 13
 4.14 problem 25 part (a)
 4.15 problem 25 part (b)
 4.16 problem 25 part (c)