Edexcel C2 — Question 7 17 marks

Exam BoardEdexcel
ModuleC2 (Core Mathematics 2)
Marks17
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicAreas by integration
TypeCombined region areas
DifficultyModerate -0.3 This is a standard C2 integration question with routine factorisation, finding roots, differentiation for gradient/turning points, and calculating areas under curves. All parts follow textbook procedures with no novel problem-solving required, though the multi-part structure and area calculation between curve and line require careful setup, making it slightly easier than average overall.
Spec1.02j Manipulate polynomials: expanding, factorising, division, factor theorem1.07i Differentiate x^n: for rational n and sums1.07m Tangents and normals: gradient and equations1.08f Area between two curves: using integration

7. \begin{figure}[h]
\captionsetup{labelformat=empty} \caption{Figure 2} \includegraphics[alt={},max width=\textwidth]{e4d38009-aa70-4c55-9765-c54044ffaa31-3_771_972_1322_557}
\end{figure} Fig. 2 shows part of the curve \(C\) with equation \(y = \mathrm { f } ( x )\), where \(\mathrm { f } ( x ) = x ^ { 3 } - 6 x ^ { 2 } + 5 x\).
The curve crosses the \(x\)-axis at the origin \(O\) and at the points \(A\) and \(B\).
  1. Factorise \(\mathrm { f } ( x )\) completely.
  2. Write down the \(x\)-coordinates of the points \(A\) and \(B\).
  3. Find the gradient of \(C\) at \(A\). The region \(R\) is bounded by \(C\) and the line \(O A\), and the region \(S\) is bounded by \(C\) and the line \(A B\).
  4. Use integration to find the area of the combined regions \(R\) and \(S\), shown shaded in Fig.2. \begin{figure}[h]
    \captionsetup{labelformat=empty} \caption{Figure 3} \includegraphics[alt={},max width=\textwidth]{e4d38009-aa70-4c55-9765-c54044ffaa31-4_736_727_338_402}
    \end{figure} Fig. 3 shows a sketch of part of the curve \(C\) with equation \(y = x ^ { 3 } - 7 x ^ { 2 } + 15 x + 3 , x \geq 0\). The point \(P\), on \(C\), has \(x\)-coordinate 1 and the point \(Q\) is the minimum turning point of \(C\).
    1. Find \(\frac { \mathrm { d } y } { \mathrm {~d} x }\).
    2. Find the coordinates of \(Q\).
    3. Show that \(P Q\) is parallel to the \(x\)-axis.
    4. Calculate the area, shown shaded in Fig. 3, bounded by \(C\) and the line \(P Q\).

Question 7:
Part (a):
AnswerMarks Guidance
\(x(x^2 - 6x + 5)\)M1
\(= x(x-1)(x-5)\)M1 A1 (3 marks)
Part (b):
AnswerMarks Guidance
1 and 5B1 ft (1 mark)
Part (c):
AnswerMarks Guidance
\(\frac{dy}{dx} = 3x^2 - 12x + 5\)M1 A1
At \(x = 1\): \(\frac{dy}{dx} = 3 - 12 + 5 = -4\)A1 (3 marks)
Part (d):
AnswerMarks Guidance
\(\int(x^3 - 6x^2 + 5x)dx = \frac{x^4}{4} - \frac{6x^3}{3} + \frac{5x^2}{2}\)M1 A1
\([\ldots]_0^1 = \frac{1}{4} - 2 + \frac{5}{2} = \frac{3}{4}\) (Region \(R\))M1 A1 ft
Evaluating at 5: \(\frac{625}{4} - 250 + \frac{125}{2} = -31\frac{1}{4}\)A1
To find \(S\): \(-31\frac{1}{4} - \frac{3}{4} = -32\)M1
Total Area \(= 32 + \frac{3}{4} = 32\frac{3}{4}\)A1 (7 marks)
# Question 7:

## Part (a):
$x(x^2 - 6x + 5)$ | M1 |
$= x(x-1)(x-5)$ | M1 A1 | (3 marks)

## Part (b):
1 and 5 | B1 ft | (1 mark)

## Part (c):
$\frac{dy}{dx} = 3x^2 - 12x + 5$ | M1 A1 |
At $x = 1$: $\frac{dy}{dx} = 3 - 12 + 5 = -4$ | A1 | (3 marks)

## Part (d):
$\int(x^3 - 6x^2 + 5x)dx = \frac{x^4}{4} - \frac{6x^3}{3} + \frac{5x^2}{2}$ | M1 A1 |
$[\ldots]_0^1 = \frac{1}{4} - 2 + \frac{5}{2} = \frac{3}{4}$ (Region $R$) | M1 A1 ft |
Evaluating at 5: $\frac{625}{4} - 250 + \frac{125}{2} = -31\frac{1}{4}$ | A1 |
To find $S$: $-31\frac{1}{4} - \frac{3}{4} = -32$ | M1 |
Total Area $= 32 + \frac{3}{4} = 32\frac{3}{4}$ | A1 | (7 marks)

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7.

\begin{figure}[h]
\begin{center}
\captionsetup{labelformat=empty}
\caption{Figure 2}
  \includegraphics[alt={},max width=\textwidth]{e4d38009-aa70-4c55-9765-c54044ffaa31-3_771_972_1322_557}
\end{center}
\end{figure}

Fig. 2 shows part of the curve $C$ with equation $y = \mathrm { f } ( x )$, where $\mathrm { f } ( x ) = x ^ { 3 } - 6 x ^ { 2 } + 5 x$.\\
The curve crosses the $x$-axis at the origin $O$ and at the points $A$ and $B$.
\begin{enumerate}[label=(\alph*)]
\item Factorise $\mathrm { f } ( x )$ completely.
\item Write down the $x$-coordinates of the points $A$ and $B$.
\item Find the gradient of $C$ at $A$.

The region $R$ is bounded by $C$ and the line $O A$, and the region $S$ is bounded by $C$ and the line $A B$.
\item Use integration to find the area of the combined regions $R$ and $S$, shown shaded in Fig.2.

\begin{figure}[h]
\begin{center}
\captionsetup{labelformat=empty}
\caption{Figure 3}
  \includegraphics[alt={},max width=\textwidth]{e4d38009-aa70-4c55-9765-c54044ffaa31-4_736_727_338_402}
\end{center}
\end{figure}

Fig. 3 shows a sketch of part of the curve $C$ with equation $y = x ^ { 3 } - 7 x ^ { 2 } + 15 x + 3 , x \geq 0$. The point $P$, on $C$, has $x$-coordinate 1 and the point $Q$ is the minimum turning point of $C$.\\
(a) Find $\frac { \mathrm { d } y } { \mathrm {~d} x }$.\\
(b) Find the coordinates of $Q$.\\
(c) Show that $P Q$ is parallel to the $x$-axis.\\
(d) Calculate the area, shown shaded in Fig. 3, bounded by $C$ and the line $P Q$.
\end{enumerate}

\hfill \mbox{\textit{Edexcel C2  Q7 [17]}}