CAIE P2 2012 June — Question 3 5 marks

Exam BoardCAIE
ModuleP2 (Pure Mathematics 2)
Year2012
SessionJune
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicPolynomial Division & Manipulation
TypeFactorisation After Division or Remainder
DifficultyModerate -0.3 Part (i) is a straightforward polynomial division requiring algebraic manipulation to find quotient and remainder. Part (ii) requires recognizing that changing 13 to 9 means subtracting the remainder 4, allowing factorization using the quotient from part (i). This is a standard A-level technique with clear scaffolding, slightly easier than average due to the helpful 'hence' structure.
Spec1.02j Manipulate polynomials: expanding, factorising, division, factor theorem1.02k Simplify rational expressions: factorising, cancelling, algebraic division

3
  1. Find the quotient when the polynomial $$8 x ^ { 3 } - 4 x ^ { 2 } - 18 x + 13$$ is divided by \(4 x ^ { 2 } + 4 x - 3\), and show that the remainder is 4 .
  2. Hence, or otherwise, factorise the polynomial $$8 x ^ { 3 } - 4 x ^ { 2 } - 18 x + 9$$

AnswerMarks Guidance
(i) Attempt division, or equivalent, at least as far as quotient \(2x + k\)M1
Obtain quotient \(2x - 3\)A1
Complete process to confirm remainder is \(4\)A1 [3]
(ii) State or imply \((4x^2 + 4x - 3)\) is a factorB1
Obtain \((2x - 3)(2x - 1)(2x + 3)\)B1 [2]
**(i)** Attempt division, or equivalent, at least as far as quotient $2x + k$ | M1 |
Obtain quotient $2x - 3$ | A1 |
Complete process to confirm remainder is $4$ | A1 | [3]

**(ii)** State or imply $(4x^2 + 4x - 3)$ is a factor | B1 |
Obtain $(2x - 3)(2x - 1)(2x + 3)$ | B1 | [2]

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3 (i) Find the quotient when the polynomial

$$8 x ^ { 3 } - 4 x ^ { 2 } - 18 x + 13$$

is divided by $4 x ^ { 2 } + 4 x - 3$, and show that the remainder is 4 .\\
(ii) Hence, or otherwise, factorise the polynomial

$$8 x ^ { 3 } - 4 x ^ { 2 } - 18 x + 9$$

\hfill \mbox{\textit{CAIE P2 2012 Q3 [5]}}