Edexcel CP2 2021 June — Question 1

Exam BoardEdexcel
ModuleCP2 (Core Pure 2)
Year2021
SessionJune
TopicComplex numbers 2

  1. Given that
$$\begin{aligned} z _ { 1 } & = 3 \left( \cos \left( \frac { \pi } { 3 } \right) + \mathrm { i } \sin \left( \frac { \pi } { 3 } \right) \right)
z _ { 2 } & = \sqrt { 2 } \left( \cos \left( \frac { \pi } { 12 } \right) - \mathrm { i } \sin \left( \frac { \pi } { 12 } \right) \right) \end{aligned}$$
  1. write down the exact value of
    1. \(\left| Z _ { 1 } Z _ { 2 } \right|\)
    2. \(\arg \left( \mathrm { z } _ { 1 } \mathrm { z } _ { 2 } \right)\) Given that \(w = z _ { 1 } z _ { 2 }\) and that \(\arg \left( w ^ { n } \right) = 0\), where \(n \in \mathbb { Z } ^ { + }\)
  2. determine
    1. the smallest positive value of \(n\)
    2. the corresponding value of \(\left| w ^ { n } \right|\)