CAIE P2 2016 June — Question 2 5 marks

Exam BoardCAIE
ModuleP2 (Pure Mathematics 2)
Year2016
SessionJune
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicPolynomial Division & Manipulation
TypeFinding Constants from Remainder Conditions
DifficultyModerate -0.3 Part (i) is a straightforward polynomial long division requiring standard algebraic manipulation. Part (ii) requires understanding that for a factor, the remainder must be zero, leading to a simple system of two linear equations in two unknowns. This is slightly easier than average as it's a routine application of polynomial division with no conceptual surprises or extended reasoning.
Spec1.02j Manipulate polynomials: expanding, factorising, division, factor theorem1.02k Simplify rational expressions: factorising, cancelling, algebraic division

2
  1. Find the quotient and remainder when \(2 x ^ { 3 } - 7 x ^ { 2 } - 9 x + 3\) is divided by \(x ^ { 2 } - 2 x + 5\).
  2. Hence find the values of the constants \(p\) and \(q\) such that \(x ^ { 2 } - 2 x + 5\) is a factor of \(2 x ^ { 3 } - 7 x ^ { 2 } + p x + q\).

Question 2:
Part (i):
AnswerMarks Guidance
Answer/WorkingMark Guidance
Carry out division, or equivalent, at least as far as quotient \(2x+k\)M1
Obtain quotient \(2x-3\)A1
Obtain remainder \(-25x+18\)A1 [3]
Part (ii):
AnswerMarks Guidance
Answer/WorkingMark Guidance
Subtract remainder of form \(ax+b\) \((ab\neq 0)\) from \(2x^3-7x^2-9x+3\) or multiply their quotient by \(x^2-2x+5\)M1
Obtain \(p=16\) and \(q=-15\)A1 [2]
## Question 2:

### Part (i):
| Answer/Working | Mark | Guidance |
|---|---|---|
| Carry out division, or equivalent, at least as far as quotient $2x+k$ | M1 | |
| Obtain quotient $2x-3$ | A1 | |
| Obtain remainder $-25x+18$ | A1 | [3] |

### Part (ii):
| Answer/Working | Mark | Guidance |
|---|---|---|
| Subtract remainder of form $ax+b$ $(ab\neq 0)$ from $2x^3-7x^2-9x+3$ or multiply their quotient by $x^2-2x+5$ | M1 | |
| Obtain $p=16$ and $q=-15$ | A1 | [2] |

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2 (i) Find the quotient and remainder when $2 x ^ { 3 } - 7 x ^ { 2 } - 9 x + 3$ is divided by $x ^ { 2 } - 2 x + 5$.\\
(ii) Hence find the values of the constants $p$ and $q$ such that $x ^ { 2 } - 2 x + 5$ is a factor of $2 x ^ { 3 } - 7 x ^ { 2 } + p x + q$.

\hfill \mbox{\textit{CAIE P2 2016 Q2 [5]}}