OCR FP1 2008 January — Question 4 8 marks

Exam BoardOCR
ModuleFP1 (Further Pure Mathematics 1)
Year2008
SessionJanuary
Marks8
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicComplex Numbers Arithmetic
TypeMultiplication and powers of complex numbers
DifficultyModerate -0.8 This is a straightforward Further Pure 1 question testing basic complex number operations: linear combination with conjugate, squaring a complex expression, and division by a complex number. All three parts use standard techniques (conjugate multiplication for division, expanding brackets) with no conceptual difficulty or problem-solving required. While FP1 content, these are routine manipulations that are easier than average A-level questions overall.
Spec4.02e Arithmetic of complex numbers: add, subtract, multiply, divide4.02f Convert between forms: cartesian and modulus-argument

4 The complex number \(3 - 4 \mathrm { i }\) is denoted by \(z\). Giving your answers in the form \(x + \mathrm { i } y\), and showing clearly how you obtain them, find
  1. \(2 z + 5 z ^ { * }\),
  2. \(( z - \mathrm { i } ) ^ { 2 }\),
  3. \(\frac { 3 } { z }\).

4 The complex number $3 - 4 \mathrm { i }$ is denoted by $z$. Giving your answers in the form $x + \mathrm { i } y$, and showing clearly how you obtain them, find\\
(i) $2 z + 5 z ^ { * }$,\\
(ii) $( z - \mathrm { i } ) ^ { 2 }$,\\
(iii) $\frac { 3 } { z }$.

\hfill \mbox{\textit{OCR FP1 2008 Q4 [8]}}