3.1 problem 1(a)
  3.2 problem 1(b)
  3.3 problem 1(c)
  3.4 problem 1(d)
  3.5 problem 1(e)
  3.6 problem 1(f)
  3.7 problem 1(g)
  3.8 problem 1(h)
  3.9 problem 1(i)
  3.10 problem 1(j)
  3.11 problem 2(a)
  3.12 problem 2(b)
  3.13 problem 2(c)
  3.14 problem 2(d)
  3.15 problem 2(e)
  3.16 problem 2(f)
  3.17 problem 3(a)
  3.18 problem 3(b)
  3.19 problem 3(c)
  3.20 problem 3(d)
  3.21 problem 4(a)
  3.22 problem 4(b)
  3.23 problem 4(c)
  3.24 problem 6
  3.25 problem 7