Question 1414a

Complex Numbers
2014 Paper 1 Question 5 Variant

Question

It is given that z=12i.{z=- 1 - 2 \mathrm{i}.}
(a)
Without using a calculator, find the values of z3{z^3} and 1z{\displaystyle \frac{1}{z}} in cartesian form x+iy,{x + \mathrm{i}y,} showing your working.
[4]
(b)
The real numbers p{p} and q{q} are such that pz3+qz{\displaystyle pz^3 + \frac{q}{z}} is real.
Find, in terms of p,{p,} the value of q{q} and the value of pz3+qz.{\displaystyle pz^3 + \frac{q}{z}.}
[3]

Answer