Edexcel F1 2015 January — Question 3 6 marks

Exam BoardEdexcel
ModuleF1 (Further Pure Mathematics 1)
Year2015
SessionJanuary
Marks6
PaperDownload PDF ↗
TopicComplex Numbers Arithmetic
TypeEquations with conjugate of expressions
DifficultyStandard +0.8 This Further Maths question requires expanding the product involving both z and its conjugate, separating real and imaginary parts, then solving the resulting simultaneous equations. It demands algebraic manipulation beyond standard complex number exercises and involves a non-standard form that requires insight to handle efficiently.
Spec4.02a Complex numbers: real/imaginary parts, modulus, argument4.02c Complex notation: z, z*, Re(z), Im(z), |z|, arg(z)4.02e Arithmetic of complex numbers: add, subtract, multiply, divide4.02i Quadratic equations: with complex roots

3. Given that \(z = x + \mathrm { i } y\), where \(x\) and \(y\) are real numbers, solve the equation $$( z - 2 i ) \left( z ^ { * } - 2 i \right) = 21 - 12 i$$ where \(z ^ { * }\) is the complex conjugate of \(z\).

3. Given that $z = x + \mathrm { i } y$, where $x$ and $y$ are real numbers, solve the equation

$$( z - 2 i ) \left( z ^ { * } - 2 i \right) = 21 - 12 i$$

where $z ^ { * }$ is the complex conjugate of $z$.\\

\hfill \mbox{\textit{Edexcel F1 2015 Q3 [6]}}