18.1 problem Example 11.5.2 page 763
 18.2 problem Example 11.5.4 page 765
 18.3 problem Example 11.5.5 page 768
 18.4 problem (a)
 18.5 problem (b)
 18.6 problem (c)
 18.7 problem (d)
 18.8 problem (e)
 18.9 problem 1
 18.10 problem 2
 18.11 problem 3
 18.12 problem 4
 18.13 problem 5
 18.14 problem 6
 18.15 problem 7
 18.16 problem 8
 18.17 problem 11
 18.18 problem 12
 18.19 problem 13
 18.20 problem 14
 18.21 problem 15
 18.22 problem 16
 18.23 problem 17
 18.24 problem 18
 18.25 problem 19
 18.26 problem 20
 18.27 problem 21
 18.28 problem 22
 18.29 problem 23
 18.30 problem 24
 18.31 problem 25
 18.32 problem 26
 18.33 problem 27
 18.34 problem 28
 18.35 problem 29