OCR C4 2014 June — Question 1 3 marks

Exam BoardOCR
ModuleC4 (Core Mathematics 4)
Year2014
SessionJune
Marks3
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicPartial Fractions
TypeSimplify algebraic fractions by addition or subtraction
DifficultyEasy -1.2 This is a straightforward algebraic manipulation requiring finding a common denominator and combining fractions. It's simpler than typical partial fractions work (which involves decomposition) and requires only routine algebraic skills with no problem-solving insight needed.
Spec1.02k Simplify rational expressions: factorising, cancelling, algebraic division

1 Express \(x + \frac { 1 } { 1 - x } + \frac { 2 } { 1 + x }\) as a single fraction, simplifying your answer.

Question 1:
AnswerMarks Guidance
AnswerMarks Guidance
\(x(1-x^2)+(1+x)+2(1-x)\) oeM1 Condone one sign error; if M0B0, SC1 for any pair of terms correctly combined into a single fraction, may be unsimplified
\(1-x^2\) oeB1 Any correct denominator common to all three fractions
\(\frac{3-x^3}{1-x^2}\) oe caoA1 Must be fully simplified; mark the final answer; eg \(\frac{x(3-x^3)}{x(1-x^2)}\) oe may score a maximum of M1B1A0
[3]
# Question 1:

| Answer | Marks | Guidance |
|--------|-------|----------|
| $x(1-x^2)+(1+x)+2(1-x)$ oe | M1 | Condone one sign error; if M0B0, SC1 for any pair of terms correctly combined into a single fraction, may be unsimplified |
| $1-x^2$ oe | B1 | Any correct denominator common to all three fractions |
| $\frac{3-x^3}{1-x^2}$ oe cao | A1 | Must be fully simplified; mark the final answer; eg $\frac{x(3-x^3)}{x(1-x^2)}$ oe may score a maximum of M1B1A0 |
| **[3]** | | |
1 Express $x + \frac { 1 } { 1 - x } + \frac { 2 } { 1 + x }$ as a single fraction, simplifying your answer.

\hfill \mbox{\textit{OCR C4 2014 Q1 [3]}}