OCR MEI Paper 2 2022 June — Question 16 15 marks

Exam BoardOCR MEI
ModulePaper 2 (Paper 2)
Year2022
SessionJune
Marks15
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicStationary points and optimisation
TypeFind stationary point then sketch curve
DifficultyStandard +0.3 This is a standard calculus question requiring differentiation to find stationary points, second derivative test for nature, and third derivative for inflection point. While it involves a quartic polynomial requiring some algebraic manipulation and factorization, the techniques are routine A-level methods with no novel problem-solving required. The 12-mark allocation reflects computational length rather than conceptual difficulty, placing it slightly above average.
Spec1.02n Sketch curves: simple equations including polynomials1.07n Stationary points: find maxima, minima using derivatives1.07p Points of inflection: using second derivative

The equation of a curve is $$y = 6x^4 + 8x^3 - 21x^2 + 12x - 6.$$
  1. In this question you must show detailed reasoning. Determine
    [12]
  2. On the axes in the Printed Answer Booklet, sketch the curve whose equation is $$y = 6x^4 + 8x^3 - 21x^2 + 12x - 6.$$ [3]

Question 16:
AnswerMarks Guidance
16(b) M1
B1
AnswerMarks
A11.1
1.1
AnswerMarks
1.1curve with a minimum in 3rd quadrant and stationary point of
inflection in 4th quadrant and no other stationary points
(0, ‒6) identified as y-intercept (intercept must be below the x-axis
and above ‒20)
correct curve with intercepts at (‒a,0) and (b,0),
where ‒3 < a < ‒2.6 and 0.8 < b < 1.2;
minimum at (‒2, y) where ‒90 < y < ‒80 and
inflection for 0 < x < 1 and y is between the x-axis and the
y-intercept
[3]
AnswerMarks Guidance
x0 (½)
𝑑𝑦
AnswerMarks Guidance
𝑑𝑥12 (0)
x0 (½)
y‒6 (−3.875)
x0 (½)
𝑑²𝑦
AnswerMarks Guidance
𝑑𝑥²‒42 (0)
PMT
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Though we make every effort to check our resources, there may be contradictions between published support and the
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Question 16:
16 | (b) | M1
B1
A1 | 1.1
1.1
1.1 | curve with a minimum in 3rd quadrant and stationary point of
inflection in 4th quadrant and no other stationary points
(0, ‒6) identified as y-intercept (intercept must be below the x-axis
and above ‒20)
correct curve with intercepts at (‒a,0) and (b,0),
where ‒3 < a < ‒2.6 and 0.8 < b < 1.2;
minimum at (‒2, y) where ‒90 < y < ‒80 and
inflection for 0 < x < 1 and y is between the x-axis and the
y-intercept
[3]
x | 0 | (½) | 1
𝑑𝑦
𝑑𝑥 | 12 | (0) | 18
x | 0 | (½) | 1
y | ‒6 | (−3.875) | ‒1
x | 0 | (½) | 1
𝑑²𝑦
𝑑𝑥² | ‒42 | (0) | 78
PMT
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If you ever have any questions about OCR qualifications or services (including administration, logistics and teaching) please feel free to get in
touch with our customer support centre.
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support@ocr.org.uk
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ocr.org.uk/qualifications/resource-finder
ocr.org.uk
Twitter/ocrexams
/ocrexams
/company/ocr
/ocrexams
OCR is part of Cambridge University Press & Assessment, a department of the University of Cambridge.
For staff training purposes and as part of our quality assurance programme your call may be recorded or monitored. © OCR
2022 Oxford Cambridge and RSA Examinations is a Company Limited by Guarantee. Registered in England. Registered office
The Triangle Building, Shaftesbury Road, Cambridge, CB2 8EA.
Registered company number 3484466. OCR is an exempt charity.
OCR operates academic and vocational qualifications regulated by Ofqual, Qualifications Wales and CCEA as listed in their
qualifications registers including A Levels, GCSEs, Cambridge Technicals and Cambridge Nationals.
OCR provides resources to help you deliver our qualifications. These resources do not represent any particular teaching method
we expect you to use. We update our resources regularly and aim to make sure content is accurate but please check the OCR
website so that you have the most up-to-date version. OCR cannot be held responsible for any errors or omissions in these
resources.
Though we make every effort to check our resources, there may be contradictions between published support and the
specification, so it is important that you always use information in the latest specification. We indicate any specification changes
within the document itself, change the version number and provide a summary of the changes. If you do notice a discrepancy
between the specification and a resource, please contact us.
Whether you already offer OCR qualifications, are new to OCR or are thinking about switching, you can request more
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Please get in touch if you want to discuss the accessibility of resources we offer to support you in delivering our qualifications.
The equation of a curve is

$$y = 6x^4 + 8x^3 - 21x^2 + 12x - 6.$$

\begin{enumerate}[label=(\alph*)]
\item In this question you must show detailed reasoning.

Determine
\begin{itemize}
\item The coordinates of the stationary points on the curve.
\item The nature of the stationary points on the curve.
\item The $x$-coordinate of the non-stationary point of inflection on the curve.
\end{itemize}
[12]

\item On the axes in the Printed Answer Booklet, sketch the curve whose equation is
$$y = 6x^4 + 8x^3 - 21x^2 + 12x - 6.$$
[3]
\end{enumerate}

\hfill \mbox{\textit{OCR MEI Paper 2 2022 Q16 [15]}}