Edexcel AEA 2011 June — Question 7 20 marks

Exam BoardEdexcel
ModuleAEA (Advanced Extension Award)
Year2011
SessionJune
Marks20
PaperDownload PDF ↗
TopicComposite & Inverse Functions
TypeFind composite function expression
DifficultyChallenging +1.8 This AEA question requires finding stationary points via differentiation (including quotient rule), analyzing composite functions with modulus and transformations to determine constants from symmetry, and finding an inverse function by solving a quadratic then determining where m(t) = m^(-1)(t). While multi-step and requiring careful algebraic manipulation across several techniques, the individual components are standard A-level methods applied systematically rather than requiring novel insight.
Spec1.02k Simplify rational expressions: factorising, cancelling, algebraic division1.02l Modulus function: notation, relations, equations and inequalities1.02v Inverse and composite functions: graphs and conditions for existence1.02w Graph transformations: simple transformations of f(x)1.07n Stationary points: find maxima, minima using derivatives

% Figure 4 shows curves with asymptotic behavior at x = 3 \includegraphics{figure_4} Figure 4
  1. Figure 4 shows a sketch of the curve with equation \(y = f(x)\), where $$f(x) = \frac{x^2 - 5}{3-x}, \quad x \in \mathbb{R}, x \neq 3$$ The curve has a minimum at the point \(A\), with \(x\)-coordinate \(\alpha\), and a maximum at the point \(B\), with \(x\)-coordinate \(\beta\). Find the value of \(\alpha\), the value of \(\beta\) and the \(y\)-coordinates of the points \(A\) and \(B\). [5]
  2. The functions \(g\) and \(h\) are defined as follows $$g: x \to x + p \quad x \in \mathbb{R}$$ $$h: x \to |x| \quad x \in \mathbb{R}$$ where \(p\) is a constant. % Figure 5 shows curve with minimum points at C and D symmetric about y-axis \includegraphics{figure_5} Figure 5 Figure 5 shows a sketch of the curve with equation \(y = h(fg(x) + q)\), \(x \in \mathbb{R}\), \(x \neq 0\), where \(q\) is a constant. The curve is symmetric about the \(y\)-axis and has minimum points at \(C\) and \(D\).
    1. Find the value of \(p\) and the value of \(q\).
    2. Write down the coordinates of \(D\).
    [5]
  3. The function \(\mathrm{m}\) is given by $$\mathrm{m}(x) = \frac{x^2 - 5}{3-x} \quad x \in \mathbb{R}, x < \alpha$$ where \(\alpha\) is the \(x\)-coordinate of \(A\) as found in part (a).
    1. Find \(\mathrm{m}^{-1}\)
    2. Write down the domain of \(\mathrm{m}^{-1}\)
    3. Find the value of \(t\) such that \(\mathrm{m}(t) = \mathrm{m}^{-1}(t)\)
    [10]
[Total 20 marks]

% Figure 4 shows curves with asymptotic behavior at x = 3

\includegraphics{figure_4}

Figure 4

\begin{enumerate}[label=(\alph*)]
\item Figure 4 shows a sketch of the curve with equation $y = f(x)$, where
$$f(x) = \frac{x^2 - 5}{3-x}, \quad x \in \mathbb{R}, x \neq 3$$

The curve has a minimum at the point $A$, with $x$-coordinate $\alpha$, and a maximum at the point $B$, with $x$-coordinate $\beta$.

Find the value of $\alpha$, the value of $\beta$ and the $y$-coordinates of the points $A$ and $B$.
[5]

\item The functions $g$ and $h$ are defined as follows
$$g: x \to x + p \quad x \in \mathbb{R}$$
$$h: x \to |x| \quad x \in \mathbb{R}$$

where $p$ is a constant.

% Figure 5 shows curve with minimum points at C and D symmetric about y-axis

\includegraphics{figure_5}

Figure 5

Figure 5 shows a sketch of the curve with equation $y = h(fg(x) + q)$, $x \in \mathbb{R}$, $x \neq 0$, where $q$ is a constant. The curve is symmetric about the $y$-axis and has minimum points at $C$ and $D$.

\begin{enumerate}[label=(\roman*)]
\item Find the value of $p$ and the value of $q$.

\item Write down the coordinates of $D$.
\end{enumerate}
[5]

\item The function $\mathrm{m}$ is given by
$$\mathrm{m}(x) = \frac{x^2 - 5}{3-x} \quad x \in \mathbb{R}, x < \alpha$$

where $\alpha$ is the $x$-coordinate of $A$ as found in part (a).

\begin{enumerate}[label=(\roman*)]
\item Find $\mathrm{m}^{-1}$

\item Write down the domain of $\mathrm{m}^{-1}$

\item Find the value of $t$ such that $\mathrm{m}(t) = \mathrm{m}^{-1}(t)$
\end{enumerate}
[10]
\end{enumerate}
[Total 20 marks]

\hfill \mbox{\textit{Edexcel AEA 2011 Q7 [20]}}