OCR C3 2009 June — Question 8 10 marks

Exam BoardOCR
ModuleC3 (Core Mathematics 3)
Year2009
SessionJune
Marks10
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicFunction Transformations
TypeSpecific function transformation description
DifficultyStandard +0.3 This is a slightly easier than average C3 question. Part (i) tests standard transformations of logarithmic functions (translation and stretch). Part (ii) requires solving ln x = 2ln(x-6), which simplifies to a quadratic using log laws. Part (iii) is routine application of Simpson's rule. All parts follow standard procedures with no novel problem-solving required, making it marginally easier than the typical C3 question.
Spec1.02w Graph transformations: simple transformations of f(x)1.06d Natural logarithm: ln(x) function and properties1.09f Trapezium rule: numerical integration

\includegraphics{figure_4} The diagram shows the curves \(y = \ln x\) and \(y = 2 \ln(x - 6)\). The curves meet at the point \(P\) which has \(x\)-coordinate \(a\). The shaded region is bounded by the curve \(y = 2 \ln(x - 6)\) and the lines \(x = a\) and \(y = 0\).
  1. Give details of the pair of transformations which transforms the curve \(y = \ln x\) to the curve \(y = 2 \ln(x - 6)\). [3]
  2. Solve an equation to find the value of \(a\). [4]
  3. Use Simpson's rule with two strips to find an approximation to the area of the shaded region. [3]

Part (i)
AnswerMarks Guidance
Refer to translation and stretchM1 in either order; allow here equiv informal terms such as 'move', …
State translation in \(x\) direction by 6A1 or equiv; now with correct terminology
State stretch in \(y\) direction by 2A1\3 or equiv; now with correct terminology
[SC: if M0 but one transformation completely correct, give B1]
Part (ii)
AnswerMarks Guidance
State \(2\ln(x - 6) = \ln x\)B1 or \(2\ln(a - 6) = \ln a\) or equiv
Show correct use of logarithm property*M1
Attempt solution of 3-term quadraticM1 dep *M
Obtain 9 onlyA1\4 following correct solution of equation
Part (iii)
AnswerMarks Guidance
Attempt evaluation of form \(k(y_0 + 4y_1 + y_2)\)M1 any constant \(k\); maybe with \(y_0 = 0\) implied
Obtain \(\frac{1}{2} \times \ln(2 \ln 1 + 8 \ln 2 + 2 \ln 3)\)A1
Obtain 2.58A1\3 or greater accuracy 2.5808…
## Part (i)

Refer to translation and stretch | M1 | in either order; allow here equiv informal terms such as 'move', …
State translation in $x$ direction by 6 | A1 | or equiv; now with correct terminology
State stretch in $y$ direction by 2 | A1\3 | or equiv; now with correct terminology

[SC: if M0 but one transformation completely correct, give B1]

## Part (ii)

State $2\ln(x - 6) = \ln x$ | B1 | or $2\ln(a - 6) = \ln a$ or equiv
Show correct use of logarithm property | *M1 |
Attempt solution of 3-term quadratic | M1 | dep *M
Obtain 9 only | A1\4 | following correct solution of equation

## Part (iii)

Attempt evaluation of form $k(y_0 + 4y_1 + y_2)$ | M1 | any constant $k$; maybe with $y_0 = 0$ implied
Obtain $\frac{1}{2} \times \ln(2 \ln 1 + 8 \ln 2 + 2 \ln 3)$ | A1 |
Obtain 2.58 | A1\3 | or greater accuracy 2.5808…

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\includegraphics{figure_4}

The diagram shows the curves $y = \ln x$ and $y = 2 \ln(x - 6)$. The curves meet at the point $P$ which has $x$-coordinate $a$. The shaded region is bounded by the curve $y = 2 \ln(x - 6)$ and the lines $x = a$ and $y = 0$.
\begin{enumerate}[label=(\roman*)]
\item Give details of the pair of transformations which transforms the curve $y = \ln x$ to the curve $y = 2 \ln(x - 6)$. [3]
\item Solve an equation to find the value of $a$. [4]
\item Use Simpson's rule with two strips to find an approximation to the area of the shaded region. [3]
\end{enumerate}

\hfill \mbox{\textit{OCR C3 2009 Q8 [10]}}