Edexcel FP2 — Question 5 10 marks

Exam BoardEdexcel
ModuleFP2 (Further Pure Mathematics 2)
Marks10
PaperDownload PDF ↗
TopicTaylor series
TypeTaylor series about π/4
DifficultyChallenging +1.2 This is a Further Maths FP2 question requiring differentiation of sec²x and Taylor series expansion about a non-zero point. Part (a) involves chain rule and product rule with trig functions (moderately technical but guided). Part (b) requires computing derivatives at x=π/4 and assembling the Taylor series—more demanding than standard calculus but follows a clear algorithmic procedure. The 10 marks and multi-step nature place it above average difficulty, but it's a standard FP2 exercise without requiring novel insight.
Spec4.08a Maclaurin series: find series for function4.08b Standard Maclaurin series: e^x, sin, cos, ln(1+x), (1+x)^n

\(y = \sec^2 x\)
  1. Show that \(\frac{d^2 y}{dx^2} = 6 \sec^4 x - 4 \sec^2 x\). [4]
  2. Find a Taylor series expansion of \(\sec^2 x\) in ascending powers of \(\left(x - \frac{\pi}{4}\right)\), up to and including the term in \(\left(x - \frac{\pi}{4}\right)^3\). [6]

$y = \sec^2 x$

\begin{enumerate}[label=(\alph*)]
\item Show that $\frac{d^2 y}{dx^2} = 6 \sec^4 x - 4 \sec^2 x$. [4]
\item Find a Taylor series expansion of $\sec^2 x$ in ascending powers of $\left(x - \frac{\pi}{4}\right)$, up to and including the term in $\left(x - \frac{\pi}{4}\right)^3$. [6]
\end{enumerate}

\hfill \mbox{\textit{Edexcel FP2  Q5 [10]}}