1.1 problem 2(a)
  1.2 problem 2(b)
  1.3 problem 2(c)
  1.4 problem 2(d)
  1.5 problem 2(e)
  1.6 problem 3(a)
  1.7 problem 3(b)
  1.8 problem 3(c)
  1.9 problem 4(a)
  1.10 problem 4(b)
  1.11 problem 4(c)
  1.12 problem 5(a)
  1.13 problem 5(b)
  1.14 problem 5(c)
  1.15 problem 5(d)
  1.16 problem 8(a)
  1.17 problem 9
  1.18 problem 10(a)