Edexcel F1 2024 January — Question 9 6 marks

Exam BoardEdexcel
ModuleF1 (Further Pure Mathematics 1)
Year2024
SessionJanuary
Marks6
PaperDownload PDF ↗
TopicComplex Numbers Arithmetic
TypeParameter from argument condition
DifficultyStandard +0.8 This is a Further Maths question requiring algebraic manipulation of complex fractions, expressing in Cartesian form with parameters, then using the argument condition to solve a quadratic. It combines multiple techniques (complex division, equating real/imaginary parts, argument formula) but follows a clear structured path without requiring deep insight.
Spec4.02a Complex numbers: real/imaginary parts, modulus, argument4.02b Express complex numbers: cartesian and modulus-argument forms

  1. Given that
$$\frac { 3 z - 1 } { 2 } = \frac { \lambda + 5 i } { \lambda - 4 i }$$ where \(\lambda\) is a real constant,
  1. determine \(z\), giving your answer in the form \(x + y i\), where \(x\) and \(y\) are real and in terms of \(\lambda\). Given also that \(\arg z = \frac { \pi } { 4 }\)
  2. find the possible values of \(\lambda\).

\begin{enumerate}
  \item Given that
\end{enumerate}

$$\frac { 3 z - 1 } { 2 } = \frac { \lambda + 5 i } { \lambda - 4 i }$$

where $\lambda$ is a real constant,\\
(a) determine $z$, giving your answer in the form $x + y i$, where $x$ and $y$ are real and in terms of $\lambda$.

Given also that $\arg z = \frac { \pi } { 4 }$\\
(b) find the possible values of $\lambda$.

\hfill \mbox{\textit{Edexcel F1 2024 Q9 [6]}}