OCR FP3 — Question 1 3 marks

Exam BoardOCR
ModuleFP3 (Further Pure Mathematics 3)
Marks3
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicComplex Numbers Argand & Loci
TypeCircle equations in complex form
DifficultyEasy -1.2 This is a straightforward Further Maths question testing basic complex number properties. Part (i) is direct verification using standard notation (1 mark), and part (ii) requires recognizing that |z|²=9 means |z|=3, which is a circle of radius 3—a standard locus result requiring minimal problem-solving.
Spec4.02a Complex numbers: real/imaginary parts, modulus, argument4.02o Loci in Argand diagram: circles, half-lines

  1. By writing \(z\) in the form \(re^{i\theta}\), show that \(zz^* = |z|^2\). [1]
  2. Given that \(zz^* = 9\), describe the locus of \(z\). [2]

\begin{enumerate}[label=(\roman*)]
\item By writing $z$ in the form $re^{i\theta}$, show that $zz^* = |z|^2$. [1]
\item Given that $zz^* = 9$, describe the locus of $z$. [2]
\end{enumerate}

\hfill \mbox{\textit{OCR FP3  Q1 [3]}}