Edexcel AEA 2018 June — Question 4 13 marks

Exam BoardEdexcel
ModuleAEA (Advanced Extension Award)
Year2018
SessionJune
Marks13
PaperDownload PDF ↗
TopicFunction Transformations
TypeInverse transformation or reflection
DifficultyChallenging +1.2 This is a structured multi-part question on function transformations and inverses. Parts (a)-(d) involve standard transformations and basic curve analysis (asymptotes, intercepts). Part (e) requires finding an inverse function of a rational function, and part (f) involves solving a functional equation. While it requires careful algebraic manipulation and understanding of inverse functions under reflection in y=-x, the steps are methodical and follow standard A-level techniques. The AEA context suggests slightly elevated difficulty, but this is more accessible than typical AEA proof questions.
Spec1.02k Simplify rational expressions: factorising, cancelling, algebraic division1.02v Inverse and composite functions: graphs and conditions for existence1.02w Graph transformations: simple transformations of f(x)

4.A curve \(C\) has equation \(y = \mathrm { f } ( x )\) where \(x \in \mathbb { R }\) and f is a one-one function.
  1. Describe a single transformation that transforms \(C\) to the curve with equation \(y = - \mathrm { f } ( - x )\) . The curve \(C\) is reflected in the line with equation \(y = - x\) to give the curve \(V\) . The equation of \(V\) is \(y = \mathrm { g } ( x )\) .
  2. Explain why \(\mathrm { g } ^ { - 1 } ( x ) = - \mathrm { f } ( - x )\) . \begin{figure}[h]
    \includegraphics[alt={},max width=\textwidth]{2a7c2530-a93c-4a26-bc37-c20c0f40c8f2-3_793_979_819_633} \captionsetup{labelformat=empty} \caption{Figure 1}
    \end{figure} Figure 1 shows a sketch of the curve \(C\) with equation \(y = \mathrm { f } ( x )\) where $$\mathrm { f } ( x ) = \frac { 3 ( x - 1 ) } { x - 2 } \quad x \in \mathbb { R } , x \neq 2$$ The curve has asymptotes with equations \(x = p\) and \(y = q\) and \(C\) crosses the \(x\)-axis at the point \(A\) and the \(y\)-axis at the point \(B\) .
  3. Write down the value of \(p\) and the value of \(q\) .
  4. Write down the coordinates of the point \(A\) and the coordinates of the point \(B\) . Given the definition of \(\mathrm { g } ( x )\) in part(b),
  5. find the function g .
  6. Solve \(\mathrm { g } ^ { - 1 } \mathrm { f } ( x ) = x\)

4.A curve $C$ has equation $y = \mathrm { f } ( x )$ where $x \in \mathbb { R }$ and f is a one-one function.
\begin{enumerate}[label=(\alph*)]
\item Describe a single transformation that transforms $C$ to the curve with equation $y = - \mathrm { f } ( - x )$ .

The curve $C$ is reflected in the line with equation $y = - x$ to give the curve $V$ . The equation of $V$ is $y = \mathrm { g } ( x )$ .
\item Explain why $\mathrm { g } ^ { - 1 } ( x ) = - \mathrm { f } ( - x )$ .

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{2a7c2530-a93c-4a26-bc37-c20c0f40c8f2-3_793_979_819_633}
\captionsetup{labelformat=empty}
\caption{Figure 1}
\end{center}
\end{figure}

Figure 1 shows a sketch of the curve $C$ with equation $y = \mathrm { f } ( x )$ where

$$\mathrm { f } ( x ) = \frac { 3 ( x - 1 ) } { x - 2 } \quad x \in \mathbb { R } , x \neq 2$$

The curve has asymptotes with equations $x = p$ and $y = q$ and $C$ crosses the $x$-axis at the point $A$ and the $y$-axis at the point $B$ .
\item Write down the value of $p$ and the value of $q$ .
\item Write down the coordinates of the point $A$ and the coordinates of the point $B$ .

Given the definition of $\mathrm { g } ( x )$ in part(b),
\item find the function g .
\item Solve $\mathrm { g } ^ { - 1 } \mathrm { f } ( x ) = x$
\end{enumerate}

\hfill \mbox{\textit{Edexcel AEA 2018 Q4 [13]}}