CAIE P2 2024 November — Question 3 7 marks

Exam BoardCAIE
ModuleP2 (Pure Mathematics 2)
Year2024
SessionNovember
Marks7
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicDifferentiating Transcendental Functions
TypeFind gradient at a point - direct evaluation
DifficultyModerate -0.3 Part (a) requires chain rule application to differentiate tan²(x/2), then direct substitution - a standard A-level technique. Part (b) involves integrating tan²(x) using the identity tan²(x) = sec²(x) - 1, plus a routine sin(x) integral. Both parts are textbook exercises requiring familiar techniques without novel problem-solving, making this slightly easier than average.
Spec1.07k Differentiate trig: sin(kx), cos(kx), tan(kx)1.08c Integrate e^(kx), 1/x, sin(kx), cos(kx)

3 The function f is defined by \(\mathrm { f } ( x ) = \tan ^ { 2 } \left( \frac { 1 } { 2 } x \right)\) for \(0 \leqslant x < \pi\).
  1. Find the exact value of \(\mathrm { f } ^ { \prime } \left( \frac { 2 } { 3 } \pi \right)\). \includegraphics[max width=\textwidth, alt={}, center]{dcc483e9-630e-4f02-ad8c-4a27c0720fc6-05_2726_33_97_22}
  2. Find the exact value of \(\int _ { 0 } ^ { \frac { 1 } { 2 } \pi } ( \mathrm { f } ( x ) + \sin x ) \mathrm { d } x\).

Question 3(a):
AnswerMarks Guidance
AnswerMark Guidance
Differentiate to obtain form \(k\tan\frac{1}{2}x\sec^2\frac{1}{2}x\)M1 OE. May use identities before differentiation
Obtain correct \(\tan\frac{1}{2}x\sec^2\frac{1}{2}x\)A1 OE. Allow unsimplified
Substitute \(\frac{2}{3}\pi\) to obtain \(4\sqrt{3}\)A1
Question 3(b):
AnswerMarks Guidance
AnswerMark Guidance
Express integrand as \(\sec^2\frac{1}{2}x - 1 + \sin x\)B1
Integrate to obtain \(k_1\tan\frac{1}{2}x - x + k_2\cos x\)M1 Where \(k_1k_2 \neq 0\)
Obtain correct \(2\tan\frac{1}{2}x - x - \cos x\)A1
Apply limits correctly to obtain \(3 - \frac{1}{2}\pi\) or exact equivalentA1
## Question 3(a):

| Answer | Mark | Guidance |
|--------|------|----------|
| Differentiate to obtain form $k\tan\frac{1}{2}x\sec^2\frac{1}{2}x$ | M1 | OE. May use identities before differentiation |
| Obtain correct $\tan\frac{1}{2}x\sec^2\frac{1}{2}x$ | A1 | OE. Allow unsimplified |
| Substitute $\frac{2}{3}\pi$ to obtain $4\sqrt{3}$ | A1 | |

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## Question 3(b):

| Answer | Mark | Guidance |
|--------|------|----------|
| Express integrand as $\sec^2\frac{1}{2}x - 1 + \sin x$ | B1 | |
| Integrate to obtain $k_1\tan\frac{1}{2}x - x + k_2\cos x$ | M1 | Where $k_1k_2 \neq 0$ |
| Obtain correct $2\tan\frac{1}{2}x - x - \cos x$ | A1 | |
| Apply limits correctly to obtain $3 - \frac{1}{2}\pi$ or exact equivalent | A1 | |

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3 The function f is defined by $\mathrm { f } ( x ) = \tan ^ { 2 } \left( \frac { 1 } { 2 } x \right)$ for $0 \leqslant x < \pi$.
\begin{enumerate}[label=(\alph*)]
\item Find the exact value of $\mathrm { f } ^ { \prime } \left( \frac { 2 } { 3 } \pi \right)$.\\

\includegraphics[max width=\textwidth, alt={}, center]{dcc483e9-630e-4f02-ad8c-4a27c0720fc6-05_2726_33_97_22}
\item Find the exact value of $\int _ { 0 } ^ { \frac { 1 } { 2 } \pi } ( \mathrm { f } ( x ) + \sin x ) \mathrm { d } x$.
\end{enumerate}

\hfill \mbox{\textit{CAIE P2 2024 Q3 [7]}}