Edexcel AEA 2016 June — Question 7 24 marks

Exam BoardEdexcel
ModuleAEA (Advanced Extension Award)
Year2016
SessionJune
Marks24
PaperDownload PDF ↗
TopicPolynomial Division & Manipulation
TypeFinding Range Restrictions via Set of k Values
DifficultyChallenging +1.8 This AEA question requires finding range restrictions via discriminant analysis, identifying asymptotes, solving rational equations, finding integer solutions (Diophantine-style), and applying transformations. While multi-part and requiring several techniques, each component follows standard methods without requiring exceptional insight. The integer pairs part (d) and transformation part (e) add moderate challenge beyond typical A-level, justifying above-average difficulty for AEA material.
Spec1.02k Simplify rational expressions: factorising, cancelling, algebraic division1.02n Sketch curves: simple equations including polynomials1.02w Graph transformations: simple transformations of f(x)

7. (a) Find the set of values of \(k\) for which the equation $$\frac { x ^ { 2 } + 3 x + 8 } { x ^ { 2 } + x - 2 } = k$$ has no real roots. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{0214eebf-93f2-4338-9222-443000115225-5_718_869_511_603} \captionsetup{labelformat=empty} \caption{Figure 3}
\end{figure} Figure 3 shows a sketch of the curve \(C _ { 1 }\) with equation \(y = \mathrm { f } ( x )\) where \(\mathrm { f } ( x ) = \frac { x ^ { 2 } + 3 x + 8 } { x ^ { 2 } + x - 2 }\) The curve has asymptotes \(x = a , x = b\) and \(y = c\), where \(a , b\) and \(c\) are integers.
(b) Find the value of \(a\), the value of \(b\) and the value of \(c\).
(c) Find the coordinates of the points of intersection of \(C _ { 1 }\) with the line \(y = 2\) (d) Find all the integer pairs \(( r , s )\) that satisfy \(s = \frac { r ^ { 2 } + 3 r + 8 } { r ^ { 2 } + r - 2 }\) The curve \(C _ { 2 }\) has equation \(y = \mathrm { g } ( x )\) where \(\mathrm { g } ( x ) = \frac { 2 x ^ { 2 } - 4 x + 6 } { x ^ { 2 } - 3 x }\) (e) Show that, for suitable integers \(m\) and \(n , \mathrm {~g} ( x )\) can be written in the form \(\mathrm { f } ( x + m ) + n\).
(f) Sketch \(C _ { 2 }\) showing any asymptotes and stating their equations.

7. (a) Find the set of values of $k$ for which the equation

$$\frac { x ^ { 2 } + 3 x + 8 } { x ^ { 2 } + x - 2 } = k$$

has no real roots.

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{0214eebf-93f2-4338-9222-443000115225-5_718_869_511_603}
\captionsetup{labelformat=empty}
\caption{Figure 3}
\end{center}
\end{figure}

Figure 3 shows a sketch of the curve $C _ { 1 }$ with equation $y = \mathrm { f } ( x )$ where $\mathrm { f } ( x ) = \frac { x ^ { 2 } + 3 x + 8 } { x ^ { 2 } + x - 2 }$ The curve has asymptotes $x = a , x = b$ and $y = c$, where $a , b$ and $c$ are integers.\\
(b) Find the value of $a$, the value of $b$ and the value of $c$.\\
(c) Find the coordinates of the points of intersection of $C _ { 1 }$ with the line $y = 2$\\
(d) Find all the integer pairs $( r , s )$ that satisfy $s = \frac { r ^ { 2 } + 3 r + 8 } { r ^ { 2 } + r - 2 }$

The curve $C _ { 2 }$ has equation $y = \mathrm { g } ( x )$ where $\mathrm { g } ( x ) = \frac { 2 x ^ { 2 } - 4 x + 6 } { x ^ { 2 } - 3 x }$\\
(e) Show that, for suitable integers $m$ and $n , \mathrm {~g} ( x )$ can be written in the form $\mathrm { f } ( x + m ) + n$.\\
(f) Sketch $C _ { 2 }$ showing any asymptotes and stating their equations.

\hfill \mbox{\textit{Edexcel AEA 2016 Q7 [24]}}