SPS SPS FM Pure 2025 February — Question 5 9 marks

Exam BoardSPS
ModuleSPS FM Pure (SPS FM Pure)
Year2025
SessionFebruary
Marks9
TopicComplex Numbers Argand & Loci
TypeCircle equations in complex form
DifficultyStandard +0.3 This is a straightforward Further Maths complex numbers question requiring standard techniques: finding circle center/radius from diameter endpoints (midpoint formula and distance), then solving simultaneous circle equations. The intersection calculation involves algebraic manipulation but follows a routine method. While it's a multi-part question worth 9 marks, it requires no novel insight—just careful application of well-practiced techniques, making it slightly easier than average.
Spec4.02a Complex numbers: real/imaginary parts, modulus, argument4.02k Argand diagrams: geometric interpretation

In an Argand diagram, the points \(A\) and \(B\) are represented by the complex numbers \(-3 + 2i\) and \(5 - 4i\) respectively. The points \(A\) and \(B\) are the end points of a diameter of a circle \(C\).
  1. Find the equation of \(C\), giving your answer in the form $$|z - a| = b \quad a \in \mathbb{C}, \quad b \in \mathbb{R}$$ [3]
The circle \(D\), with equation \(|z - 2 - 3i| = 2\), intersects \(C\) at the points representing the complex numbers \(z_1\) and \(z_2\).
  1. Find the complex numbers \(z_1\) and \(z_2\). [6]

In an Argand diagram, the points $A$ and $B$ are represented by the complex numbers $-3 + 2i$ and $5 - 4i$ respectively. The points $A$ and $B$ are the end points of a diameter of a circle $C$.

\begin{enumerate}[label=(\alph*)]
\item Find the equation of $C$, giving your answer in the form
$$|z - a| = b \quad a \in \mathbb{C}, \quad b \in \mathbb{R}$$
[3]
\end{enumerate}

The circle $D$, with equation $|z - 2 - 3i| = 2$, intersects $C$ at the points representing the complex numbers $z_1$ and $z_2$.

\begin{enumerate}[label=(\alph*)]
\setcounter{enumi}{1}
\item Find the complex numbers $z_1$ and $z_2$. [6]
\end{enumerate}

\hfill \mbox{\textit{SPS SPS FM Pure 2025 Q5 [9]}}