AQA FP2 2013 June — Question 6 8 marks

Exam BoardAQA
ModuleFP2 (Further Pure Mathematics 2)
Year2013
SessionJune
Marks8
PaperDownload PDF ↗
TopicHyperbolic functions
TypeIntegrate using hyperbolic substitution
DifficultyChallenging +1.2 This is a structured Further Maths question requiring hyperbolic function manipulation and substitution integration. Part (a) is routine algebraic manipulation using standard definitions. Part (b) follows a guided substitution leading to a standard inverse tan integral. While requiring multiple techniques, the question provides clear scaffolding and uses well-practiced methods for FP2 students, making it moderately above average difficulty but not requiring novel insight.
Spec1.05i Inverse trig functions: arcsin, arccos, arctan domains and graphs1.08h Integration by substitution4.07a Hyperbolic definitions: sinh, cosh, tanh as exponentials

6
  1. Show that \(\frac { 1 } { 5 \cosh x - 3 \sinh x } = \frac { \mathrm { e } ^ { x } } { m + \mathrm { e } ^ { 2 x } }\), where \(m\) is an integer.
  2. Use the substitution \(u = \mathrm { e } ^ { x }\) to show that $$\int _ { 0 } ^ { \ln 2 } \frac { 1 } { 5 \cosh x - 3 \sinh x } \mathrm {~d} x = \frac { \pi } { 8 } - \frac { 1 } { 2 } \tan ^ { - 1 } \left( \frac { 1 } { 2 } \right)$$

6
\begin{enumerate}[label=(\alph*)]
\item Show that $\frac { 1 } { 5 \cosh x - 3 \sinh x } = \frac { \mathrm { e } ^ { x } } { m + \mathrm { e } ^ { 2 x } }$, where $m$ is an integer.
\item Use the substitution $u = \mathrm { e } ^ { x }$ to show that

$$\int _ { 0 } ^ { \ln 2 } \frac { 1 } { 5 \cosh x - 3 \sinh x } \mathrm {~d} x = \frac { \pi } { 8 } - \frac { 1 } { 2 } \tan ^ { - 1 } \left( \frac { 1 } { 2 } \right)$$
\end{enumerate}

\hfill \mbox{\textit{AQA FP2 2013 Q6 [8]}}