AQA Further Paper 2 2021 June — Question 8 6 marks

Exam BoardAQA
ModuleFurther Paper 2 (Further Paper 2)
Year2021
SessionJune
Marks6
TopicComplex Numbers Argand & Loci

8 The complex number \(z\) satisfies the equations $$\left| z ^ { * } - 1 - 2 i \right| = | z - 3 |$$ and $$| z - a | = 3$$ where \(a\) is real.
Show that \(a\) must lie in the interval \([ 1 - s \sqrt { t } , 1 + s \sqrt { t } ]\), where \(s\) and \(t\) are prime numbers.
[0pt] [6 marks]