Edexcel FP2 Specimen — Question 8 14 marks

Exam BoardEdexcel
ModuleFP2 (Further Pure Mathematics 2)
SessionSpecimen
Marks14
PaperDownload PDF ↗
TopicComplex numbers 2
TypeIntegration using De Moivre identities
DifficultyChallenging +1.2 This is a standard FP2 De Moivre question with three routine parts: (a) proving a standard identity using z = e^(iθ), (b) expressing cos^4θ in terms of multiple angles using binomial expansion and part (a), and (c) applying a volume of revolution formula. While it requires knowledge of Further Maths content and multiple techniques, each step follows a well-established procedure with no novel insight required. The multi-part structure and integration of complex numbers with calculus places it above average difficulty, but it remains a textbook-style exercise.
Spec4.02n Euler's formula: e^(i*theta) = cos(theta) + i*sin(theta)4.02q De Moivre's theorem: multiple angle formulae4.08d Volumes of revolution: about x and y axes

  1. (a) Given that \(z = e ^ { i \theta }\), show that
$$z ^ { p } + \frac { 1 } { z ^ { p } } = 2 \cos p \theta$$ where \(p\) is a positive integer.
(b) Given that $$\cos ^ { 4 } \theta = A \cos 4 \theta + B \cos 2 \theta + C$$ find the values of the constants \(A , B\) and \(C\). The region \(R\) bounded by the curve with equation \(y = \cos ^ { 2 } x , - \frac { \pi } { 2 } \leq x \leq \frac { \pi } { 2 }\), and the \(x\)-axis is rotated through \(2 \pi\) about the \(x\)-axis.
(c) Find the volume of the solid generated.

\begin{enumerate}
  \item (a) Given that $z = e ^ { i \theta }$, show that
\end{enumerate}

$$z ^ { p } + \frac { 1 } { z ^ { p } } = 2 \cos p \theta$$

where $p$ is a positive integer.\\
(b) Given that

$$\cos ^ { 4 } \theta = A \cos 4 \theta + B \cos 2 \theta + C$$

find the values of the constants $A , B$ and $C$.

The region $R$ bounded by the curve with equation $y = \cos ^ { 2 } x , - \frac { \pi } { 2 } \leq x \leq \frac { \pi } { 2 }$, and the $x$-axis is rotated through $2 \pi$ about the $x$-axis.\\
(c) Find the volume of the solid generated.

\hfill \mbox{\textit{Edexcel FP2  Q8 [14]}}