OCR C4 2012 January — Question 1 3 marks

Exam BoardOCR
ModuleC4 (Core Mathematics 4)
Year2012
SessionJanuary
Marks3
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicPolynomial Division & Manipulation
TypeFinding Polynomial from Division Information
DifficultyModerate -0.8 This is a straightforward application of the division algorithm for polynomials: f(x) = (divisor)(quotient) + remainder. Students simply multiply out (x² + 1)(x² + 4x + 2) and add (x - 1), requiring only algebraic expansion with no problem-solving or conceptual insight.
Spec1.02j Manipulate polynomials: expanding, factorising, division, factor theorem

1 When the polynomial \(\mathrm { f } ( x )\) is divided by \(x ^ { 2 } + 1\), the quotient is \(x ^ { 2 } + 4 x + 2\) and the remainder is \(x - 1\). Find \(\mathrm { f } ( x )\), simplifying your answer.

Question 1:
AnswerMarks Guidance
AnswerMarks Guidance
\(f(x) = (x^2+1)(x^2+4x+2)+(x-1)\)M1 Written or clearly intended. Alt: Long div with 3 stages/equate quots/equate rems
\(x^4 + 4x^3 + \ldots\)B1
\(+ \ldots 3x^2 + 5x + 1\)A1
[3]
## Question 1:

| Answer | Marks | Guidance |
|--------|-------|----------|
| $f(x) = (x^2+1)(x^2+4x+2)+(x-1)$ | M1 | Written or clearly intended. Alt: Long div with 3 stages/equate quots/equate rems |
| $x^4 + 4x^3 + \ldots$ | B1 | |
| $+ \ldots 3x^2 + 5x + 1$ | A1 | |
| **[3]** | | |

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1 When the polynomial $\mathrm { f } ( x )$ is divided by $x ^ { 2 } + 1$, the quotient is $x ^ { 2 } + 4 x + 2$ and the remainder is $x - 1$. Find $\mathrm { f } ( x )$, simplifying your answer.

\hfill \mbox{\textit{OCR C4 2012 Q1 [3]}}