CAIE P2 2019 June — Question 5 8 marks

Exam BoardCAIE
ModuleP2 (Pure Mathematics 2)
Year2019
SessionJune
Marks8
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicPolynomial Division & Manipulation
TypeIntegration Using Polynomial Division
DifficultyStandard +0.3 This is a straightforward two-part question requiring polynomial long division followed by integration of the resulting quotient plus remainder term. Part (i) is routine algebraic manipulation, and part (ii) involves standard integration techniques (polynomial terms plus a logarithmic term from the remainder). The 'hence' structure guides students clearly, and expressing the final answer in the given form requires only basic logarithm laws. Slightly easier than average due to its predictable structure and standard techniques.
Spec1.02k Simplify rational expressions: factorising, cancelling, algebraic division1.08c Integrate e^(kx), 1/x, sin(kx), cos(kx)

5
  1. Find the quotient and remainder when \(2 x ^ { 3 } + x ^ { 2 } - 8 x\) is divided by ( \(2 x + 1\) ).
  2. Hence find the exact value of \(\int _ { 0 } ^ { 3 } \frac { 2 x ^ { 3 } + x ^ { 2 } - 8 x } { 2 x + 1 } \mathrm {~d} x\), giving the answer in the form \(\ln \left( k \mathrm { e } ^ { a } \right)\) where \(k\) and \(a\) are constants.

Question 5(i):
AnswerMarks Guidance
AnswerMark Guidance
Carry out division to obtain quotient of form \(x^2 + k\)M1
Obtain quotient \(x^2 - 4\)A1 Allow use of an identity
Obtain remainder 4A1 SC: If only the remainder theorem is used to obtain 4 then B1
Question 5(ii):
AnswerMarks Guidance
AnswerMark Guidance
Integrate to obtain at least \(k_1x^3\) and \(k_2\ln(2x+1)\) terms using the result from (i)*M1
Obtain correct \(\frac{1}{3}x^3 - 4x + 2\ln(2x+1)\)A1
Apply limits and note or imply that constant \(k_3\) can be written \(\ln e^{k_3}\)DM1
Apply appropriate logarithm properties correctlyM1
Obtain \(\ln(49e^{-3})\)A1
## Question 5(i):

| Answer | Mark | Guidance |
|--------|------|----------|
| Carry out division to obtain quotient of form $x^2 + k$ | M1 | |
| Obtain quotient $x^2 - 4$ | A1 | Allow use of an identity |
| Obtain remainder 4 | A1 | **SC**: If only the remainder theorem is used to obtain 4 then B1 |

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## Question 5(ii):

| Answer | Mark | Guidance |
|--------|------|----------|
| Integrate to obtain at least $k_1x^3$ and $k_2\ln(2x+1)$ terms using the result from (i) | *M1 | |
| Obtain correct $\frac{1}{3}x^3 - 4x + 2\ln(2x+1)$ | A1 | |
| Apply limits and note or imply that constant $k_3$ can be written $\ln e^{k_3}$ | DM1 | |
| Apply appropriate logarithm properties correctly | M1 | |
| Obtain $\ln(49e^{-3})$ | A1 | |

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5 (i) Find the quotient and remainder when $2 x ^ { 3 } + x ^ { 2 } - 8 x$ is divided by ( $2 x + 1$ ).\\

(ii) Hence find the exact value of $\int _ { 0 } ^ { 3 } \frac { 2 x ^ { 3 } + x ^ { 2 } - 8 x } { 2 x + 1 } \mathrm {~d} x$, giving the answer in the form $\ln \left( k \mathrm { e } ^ { a } \right)$ where $k$ and $a$ are constants.\\

\hfill \mbox{\textit{CAIE P2 2019 Q5 [8]}}