4.1 problem Problem 2(a)
 4.2 problem Problem 2(b)
 4.3 problem Problem 2(c)
 4.4 problem Problem 2(d)
 4.5 problem Problem 2(e)
 4.6 problem Problem 2(f)
 4.7 problem Problem 2(g)
 4.8 problem Problem 2(h)
 4.9 problem Problem 2(i)
 4.10 problem Problem 2(i)[j]
 4.11 problem Problem 2(j)[k]
 4.12 problem Problem 2(k)[l]
 4.13 problem Problem 2(m)
 4.14 problem Problem 2(l)[n]
 4.15 problem Problem 3(a)
 4.16 problem Problem 3(b)
 4.17 problem Problem 3(c)
 4.18 problem Problem 3(d)
 4.19 problem Problem 3(e)
 4.20 problem Problem 3(f)
 4.21 problem Problem 3(g)
 4.22 problem Problem 3(h)
 4.23 problem Problem 3(i)
 4.24 problem Problem 3(j)
 4.25 problem Problem 4(a)
 4.26 problem Problem 4(b)
 4.27 problem Problem 4(c)
 4.28 problem Problem 4(d)
 4.29 problem Problem 4(e)
 4.30 problem Problem 5(a)
 4.31 problem Problem 5(b)
 4.32 problem Problem 5(c)
 4.33 problem Problem 5(d)
 4.34 problem Problem 5(e)
 4.35 problem Problem 5(f)
 4.36 problem Problem 6(a)
 4.37 problem Problem 13(a)
 4.38 problem Problem 13(b)
 4.39 problem Problem 13(c)
 4.40 problem Problem 13(d)
 4.41 problem Problem 14(a)
 4.42 problem Problem 14(b)