OCR H240/01 2022 June — Question 3 7 marks

Exam BoardOCR
ModuleH240/01 (Pure Mathematics)
Year2022
SessionJune
Marks7
PaperDownload PDF ↗
TopicAreas Between Curves
TypeArea with Inequality Constraints
DifficultyModerate -0.8 This is a straightforward multi-part question requiring standard techniques: solving simultaneous quadratic equations by equating and factorising, sketching a linear function, and shading an inequality region. All components are routine A-level procedures with no problem-solving insight required, making it easier than average.
Spec1.02c Simultaneous equations: two variables by elimination and substitution1.02i Represent inequalities: graphically on coordinate plane

3
  1. In this question you must show detailed reasoning.
    Find the coordinates of the points of intersection of the curves with equations \(y = x ^ { 2 } - 2 x + 1\) and \(y = - x ^ { 2 } + 6 x - 5\).
  2. The diagram shows the curves \(y = x ^ { 2 } - 2 x + 1\) and \(y = - x ^ { 2 } + 6 x - 5\). This diagram is repeated in the Printed Answer Booklet. \includegraphics[max width=\textwidth, alt={}, center]{38b515c2-4764-4b51-a1f5-9b48d46610f0-5_377_542_603_322} On the diagram in the Printed Answer Booklet, draw the line \(y = 2 x - 2\).
  3. Show on your diagram in the Printed Answer Booklet the region of the \(x - y\) plane within which all three of the following inequalities are satisfied. \(y \geqslant x ^ { 2 } - 2 x + 1 \quad y \leqslant - x ^ { 2 } + 6 x - 5 \quad y \leqslant 2 x - 2\) You should indicate the region for which all the inequalities hold by labelling the region \(R\).[1]

Question 3:
Part (a)
AnswerMarks Guidance
AnswerMarks Guidance
DR: \(2x^2 - 8x + 6 = 0\), \(x^2 - 4x + 3 = 0\)M1 Equate, and rearrange to three term quadratic. Attempt to gather like terms, but not necessarily on same side. Condone no '\(= 0\)'
\((x-1)(x-3) = 0\)M1 Attempt to solve quadratic. If factorising then expansion should give \(x^2\) and one other term correct. Quadratic formula should be correct – allow one slip when substituting. Completing the square needs to go as far as \(x - p = \pm\sqrt{q}\)
\(x = 1,\ x = 3\)A1 Obtain both correct \(x\) values. Or one correct \((x,y)\) coordinate following a correct factorisation
\((1, 0)\) and \((3, 4)\)A1 Obtain both correct pairs of coordinates. Allow as e.g. \(x=1, y=0\) as long as pairings are clear
Part (b)
AnswerMarks Guidance
AnswerMarks Guidance
Attempt graph of \(y = 2x - 2\), with positive gradient and negative interceptM1 No need for line to actually intersect with negative \(y\)-axis as long as it goes beneath positive \(x\)-axis
Graph of \(y = 2x - 2\) passing through both points of intersection of the two quadratic graphsA1 Must pass through both points
Part (c)
AnswerMarks Guidance
AnswerMarks Guidance
Correct region labelled with R, or otherwise clearly identifiedB1FT FT any straight line that splits the overlap area into two finite regions, with the lower region identified. Allow for straight line with negative gradient as well, but not \(x = k\)
# Question 3:

## Part (a)

| Answer | Marks | Guidance |
|--------|-------|----------|
| DR: $2x^2 - 8x + 6 = 0$, $x^2 - 4x + 3 = 0$ | **M1** | Equate, and rearrange to three term quadratic. Attempt to gather like terms, but not necessarily on same side. Condone no '$= 0$' |
| $(x-1)(x-3) = 0$ | **M1** | Attempt to solve quadratic. If factorising then expansion should give $x^2$ and one other term correct. Quadratic formula should be correct – allow one slip when substituting. Completing the square needs to go as far as $x - p = \pm\sqrt{q}$ |
| $x = 1,\ x = 3$ | **A1** | Obtain both correct $x$ values. Or one correct $(x,y)$ coordinate following a correct factorisation |
| $(1, 0)$ and $(3, 4)$ | **A1** | Obtain both correct pairs of coordinates. Allow as e.g. $x=1, y=0$ as long as pairings are clear |

## Part (b)

| Answer | Marks | Guidance |
|--------|-------|----------|
| Attempt graph of $y = 2x - 2$, with positive gradient and negative intercept | **M1** | No need for line to actually intersect with negative $y$-axis as long as it goes beneath positive $x$-axis |
| Graph of $y = 2x - 2$ passing through both points of intersection of the two quadratic graphs | **A1** | Must pass through both points |

## Part (c)

| Answer | Marks | Guidance |
|--------|-------|----------|
| Correct region labelled with R, or otherwise clearly identified | **B1FT** | FT any straight line that splits the overlap area into two finite regions, with the lower region identified. Allow for straight line with negative gradient as well, but not $x = k$ |

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3
\begin{enumerate}[label=(\alph*)]
\item In this question you must show detailed reasoning.\\
Find the coordinates of the points of intersection of the curves with equations $y = x ^ { 2 } - 2 x + 1$ and $y = - x ^ { 2 } + 6 x - 5$.
\item The diagram shows the curves $y = x ^ { 2 } - 2 x + 1$ and $y = - x ^ { 2 } + 6 x - 5$.

This diagram is repeated in the Printed Answer Booklet.\\
\includegraphics[max width=\textwidth, alt={}, center]{38b515c2-4764-4b51-a1f5-9b48d46610f0-5_377_542_603_322}

On the diagram in the Printed Answer Booklet, draw the line $y = 2 x - 2$.
\item Show on your diagram in the Printed Answer Booklet the region of the $x - y$ plane within which all three of the following inequalities are satisfied.\\
$y \geqslant x ^ { 2 } - 2 x + 1 \quad y \leqslant - x ^ { 2 } + 6 x - 5 \quad y \leqslant 2 x - 2$\\
You should indicate the region for which all the inequalities hold by labelling the region $R$.[1]
\end{enumerate}

\hfill \mbox{\textit{OCR H240/01 2022 Q3 [7]}}