Edexcel P2 2023 January — Question 9 8 marks

Exam BoardEdexcel
ModuleP2 (Pure Mathematics 2)
Year2023
SessionJanuary
Marks8
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicAreas Between Curves
TypeMultiple Region or Composite Area
DifficultyStandard +0.3 This is a standard A-level integration question requiring finding intersection points, setting up two definite integrals for areas between curves, and computing a ratio. While it involves multiple regions and several steps, all techniques are routine P2 content with no novel insights required. The algebraic manipulation is straightforward, making it slightly easier than average.
Spec1.02n Sketch curves: simple equations including polynomials1.08e Area between curve and x-axis: using definite integrals1.08f Area between two curves: using integration

  1. In this question you must show all stages of your working.
\section*{Solutions based entirely on calculator technology are not acceptable.} \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{f6af51c1-5f85-4952-b3c4-9dca42b2a309-26_761_940_411_566} \captionsetup{labelformat=empty} \caption{Figure 3}
\end{figure} Figure 3 shows
  • the curve \(C\) with equation \(y = x ^ { 2 } - 4 x + 5\)
  • the line \(l\) with equation \(y = 2\)
The curve \(C\) intersects the \(y\)-axis at the point \(D\).
  1. Write down the coordinates of \(D\). The curve \(C\) intersects the line \(l\) at the points \(E\) and \(F\), as shown in Figure 3.
  2. Find the \(x\) coordinate of \(E\) and the \(x\) coordinate of \(F\). Shown shaded in Figure 3 is
    • the region \(R _ { 1 }\) which is bounded by \(C , l\) and the \(y\)-axis
    • the region \(R _ { 2 }\) which is bounded by \(C\) and the line segments \(E F\) and \(D F\)
    Given that \(\frac { \text { area of } R _ { 1 } } { \text { area of } R _ { 2 } } = k\), where \(k\) is a constant,
  3. use algebraic integration to find the exact value of \(k\), giving your answer as a simplified fraction.

Question 9(a):
AnswerMarks Guidance
Working/AnswerMark Guidance
\((0,\ 5)\)B1 Correct coordinates. Allow \(x=0,\ y=5\). 5 on its own is B0.
Question 9(b):
AnswerMarks Guidance
Working/AnswerMark Guidance
\(x^2-4x+5=2 \Rightarrow x^2-4x+3=0 \Rightarrow x=\ldots\)M1 Sets \(C=l\) and solves for \(x\). Expect 3TQ \(x^2-4x+3(=0)\) before solving by factorising, formula, completing the square or calculator.
\(x(E)=1,\ x(F)=3\)A1 Correct values from correct method. Condone if \(E\) and \(F\) labelled wrong way round. Answers only scores M0A0.
Question 9(c):
AnswerMarks Guidance
Working/AnswerMark Guidance
Area \(R_1=\int_0^1(x^2-4x+5-2)\,dx=\left[\frac{x^3}{3}-2x^2+3x\right]_0^1=\frac{1}{3}-2+3=\frac{4}{3}\)M1A1 M1: Fully correct strategy for area of \(R_1\), attempting to integrate \(C-l\) or integrate \(C\) and subtract rectangle area. Limits must be based on part (b). A1: \(\frac{4}{3}\) or exact equivalent.
Area \(R_2=\frac{1}{2}\times3\times3-\text{"}\frac{4}{3}\text{"}=\frac{19}{6}\)M1A1 M1: Fully correct strategy for area of \(R_2\). Many strategies possible (e.g. \(GDF-\)"\(R_1\)", \(EDH+EHF\), \(DJFG-\)"\(R_1\)"\(-DJF\)). A1: \(\frac{19}{6}\) or exact equivalent.
\(\frac{\text{area of }R_1}{\text{area of }R_2}=\frac{\frac{4}{3}}{\frac{19}{6}}=\frac{8}{19}\)A1 cao, all previous marks must have been scored.
## Question 9(a):

| Working/Answer | Mark | Guidance |
|---|---|---|
| $(0,\ 5)$ | B1 | Correct coordinates. Allow $x=0,\ y=5$. 5 on its own is B0. |

---

## Question 9(b):

| Working/Answer | Mark | Guidance |
|---|---|---|
| $x^2-4x+5=2 \Rightarrow x^2-4x+3=0 \Rightarrow x=\ldots$ | M1 | Sets $C=l$ and solves for $x$. Expect 3TQ $x^2-4x+3(=0)$ before solving by factorising, formula, completing the square or calculator. |
| $x(E)=1,\ x(F)=3$ | A1 | Correct values from correct method. Condone if $E$ and $F$ labelled wrong way round. Answers only scores M0A0. |

---

## Question 9(c):

| Working/Answer | Mark | Guidance |
|---|---|---|
| Area $R_1=\int_0^1(x^2-4x+5-2)\,dx=\left[\frac{x^3}{3}-2x^2+3x\right]_0^1=\frac{1}{3}-2+3=\frac{4}{3}$ | M1A1 | M1: Fully correct strategy for area of $R_1$, attempting to integrate $C-l$ or integrate $C$ and subtract rectangle area. Limits must be based on part (b). A1: $\frac{4}{3}$ or exact equivalent. |
| Area $R_2=\frac{1}{2}\times3\times3-\text{"}\frac{4}{3}\text{"}=\frac{19}{6}$ | M1A1 | M1: Fully correct strategy for area of $R_2$. Many strategies possible (e.g. $GDF-$"$R_1$", $EDH+EHF$, $DJFG-$"$R_1$"$-DJF$). A1: $\frac{19}{6}$ or exact equivalent. |
| $\frac{\text{area of }R_1}{\text{area of }R_2}=\frac{\frac{4}{3}}{\frac{19}{6}}=\frac{8}{19}$ | A1 | cao, all previous marks must have been scored. |
\begin{enumerate}
  \item In this question you must show all stages of your working.
\end{enumerate}

\section*{Solutions based entirely on calculator technology are not acceptable.}
\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{f6af51c1-5f85-4952-b3c4-9dca42b2a309-26_761_940_411_566}
\captionsetup{labelformat=empty}
\caption{Figure 3}
\end{center}
\end{figure}

Figure 3 shows

\begin{itemize}
  \item the curve $C$ with equation $y = x ^ { 2 } - 4 x + 5$
  \item the line $l$ with equation $y = 2$
\end{itemize}

The curve $C$ intersects the $y$-axis at the point $D$.\\
(a) Write down the coordinates of $D$.

The curve $C$ intersects the line $l$ at the points $E$ and $F$, as shown in Figure 3.\\
(b) Find the $x$ coordinate of $E$ and the $x$ coordinate of $F$.

Shown shaded in Figure 3 is

\begin{itemize}
  \item the region $R _ { 1 }$ which is bounded by $C , l$ and the $y$-axis
  \item the region $R _ { 2 }$ which is bounded by $C$ and the line segments $E F$ and $D F$
\end{itemize}

Given that $\frac { \text { area of } R _ { 1 } } { \text { area of } R _ { 2 } } = k$, where $k$ is a constant,\\
(c) use algebraic integration to find the exact value of $k$, giving your answer as a simplified fraction.

\hfill \mbox{\textit{Edexcel P2 2023 Q9 [8]}}