CAIE P3 2010 June — Question 8

Exam BoardCAIE
ModuleP3 (Pure Mathematics 3)
Year2010
SessionJune
TopicComplex numbers 2

8 The variable complex number \(z\) is given by $$z = 1 + \cos 2 \theta + i \sin 2 \theta$$ where \(\theta\) takes all values in the interval \(- \frac { 1 } { 2 } \pi < \theta < \frac { 1 } { 2 } \pi\).
  1. Show that the modulus of \(z\) is \(2 \cos \theta\) and the argument of \(z\) is \(\theta\).
  2. Prove that the real part of \(\frac { 1 } { z }\) is constant.