CAIE P2 2002 November — Question 6 9 marks

Exam BoardCAIE
ModuleP2 (Pure Mathematics 2)
Year2002
SessionNovember
Marks9
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicStandard Integrals and Reverse Chain Rule
TypeArea under curve using integration
DifficultyModerate -0.8 This is a straightforward integration question testing standard techniques. Part (a) requires direct integration of sin 2x and cos x with simple substitution of limits. Part (b) involves integrating 1/(x+1) to get ln(x+1) and solving ln(p+1) - ln(2) = 2, which is routine manipulation. All techniques are standard textbook exercises with no problem-solving insight required, making it easier than average but not trivial due to the multi-part nature and algebraic manipulation needed.
Spec1.08c Integrate e^(kx), 1/x, sin(kx), cos(kx)1.08d Evaluate definite integrals: between limits

6
  1. Find the value of \(\int _ { 0 } ^ { \frac { 1 } { 2 } \pi } ( \sin 2 x + \cos x ) \mathrm { d } x\).
  2. \includegraphics[max width=\textwidth, alt={}, center]{9894d97f-3b7b-4dbe-b94a-2c8415442038-3_517_880_422_669} The diagram shows part of the curve \(y = \frac { 1 } { x + 1 }\). The shaded region \(R\) is bounded by the curve and by the lines \(x = 1 , y = 0\) and \(x = p\).
    1. Find, in terms of \(p\), the area of \(R\).
    2. Hence find, correct to 1 decimal place, the value of \(p\) for which the area of \(R\) is equal to 2 .

AnswerMarks Guidance
(a) Obtain indefinite integral \(-\frac{1}{2}\cos 2x + \sin x\)B1 + B1
Use limits with attempted integralM1
Obtain answer 2 correctly with no errorsA1 4
(b)(i) Identify \(R\) with correct definite integral and attempt to integrateM1
Obtain indefinite integral \(\ln(x+1)\)B1
Obtain answer \(R = \ln(p+1) - \ln 2\)A1 3
(b)(ii) Use exponential method to solve an equation of the form \(\ln x = k\)M1
Obtain answer \(p = 13.8\)A1 2
**(a)** Obtain indefinite integral $-\frac{1}{2}\cos 2x + \sin x$ | B1 + B1 | 
Use limits with attempted integral | M1 | 
Obtain answer 2 correctly with no errors | A1 | 4 |

**(b)(i)** Identify $R$ with correct definite integral and attempt to integrate | M1 | 
Obtain indefinite integral $\ln(x+1)$ | B1 | 
Obtain answer $R = \ln(p+1) - \ln 2$ | A1 | 3 |

**(b)(ii)** Use exponential method to solve an equation of the form $\ln x = k$ | M1 | 
Obtain answer $p = 13.8$ | A1 | 2 |

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6
\begin{enumerate}[label=(\alph*)]
\item Find the value of $\int _ { 0 } ^ { \frac { 1 } { 2 } \pi } ( \sin 2 x + \cos x ) \mathrm { d } x$.
\item \\
\includegraphics[max width=\textwidth, alt={}, center]{9894d97f-3b7b-4dbe-b94a-2c8415442038-3_517_880_422_669}

The diagram shows part of the curve $y = \frac { 1 } { x + 1 }$. The shaded region $R$ is bounded by the curve and by the lines $x = 1 , y = 0$ and $x = p$.
\begin{enumerate}[label=(\roman*)]
\item Find, in terms of $p$, the area of $R$.
\item Hence find, correct to 1 decimal place, the value of $p$ for which the area of $R$ is equal to 2 .
\end{enumerate}\end{enumerate}

\hfill \mbox{\textit{CAIE P2 2002 Q6 [9]}}