AQA Further AS Paper 1 2021 June — Question 8

Exam BoardAQA
ModuleFurther AS Paper 1 (Further AS Paper 1)
Year2021
SessionJune
TopicComplex Numbers Arithmetic
TypeGiven two complex roots, find all roots

8 Stephen is correctly told that \(( 1 + \mathrm { i } )\) and - 1 are two roots of the polynomial equation $$z ^ { 3 } - 2 \mathrm { i } z ^ { 2 } + p z + q = 0$$ where \(p\) and \(q\) are complex numbers.
8
  1. Stephen states that ( \(1 - \mathrm { i }\) ) must also be a root of the equation because roots of polynomial equations occur in conjugate pairs. Explain why Stephen's reasoning is wrong. 8
  2. \(\quad\) Find \(p\) and \(q\)