OCR MEI FP1 2005 January — Question 7 14 marks

Exam BoardOCR MEI
ModuleFP1 (Further Pure Mathematics 1)
Year2005
SessionJanuary
Marks14
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicPolynomial Division & Manipulation
TypeSolving Inequalities with Rational Functions
DifficultyStandard +0.8 This FP1 question requires multiple techniques: finding zeros/asymptotes, analyzing end behavior, curve sketching, and solving a rational inequality. Part (v) requires algebraic manipulation to get a common denominator, factoring a quadratic, and careful sign analysis around discontinuities—more sophisticated than typical A-level pure maths but standard for Further Maths.
Spec1.02g Inequalities: linear and quadratic in single variable1.02k Simplify rational expressions: factorising, cancelling, algebraic division1.02n Sketch curves: simple equations including polynomials

7 A curve has equation \(y = \frac { ( 2 x - 3 ) ( x + 1 ) } { ( x + 4 ) ( x - 2 ) }\).
  1. Write down the values of \(x\) for which \(y = 0\).
  2. Write down the equations of the three asymptotes.
  3. Determine whether the curve approaches the horizontal asymptote from above or from below for
    (A) large positive values of \(x\),
    (B) large negative values of \(x\).
  4. Sketch the curve.
  5. Solve the inequality \(\frac { ( 2 x - 3 ) ( x + 1 ) } { ( x + 4 ) ( x - 2 ) } \leqslant 2\).

Question 7:
Part (i):
AnswerMarks Guidance
AnswerMark Guidance
\(x = \frac{3}{2}\) and \(-1\)B1, [1] Both
Part (ii):
AnswerMarks Guidance
AnswerMark Guidance
\(x = 2\), \(x = -4\) and \(y = 2\)B1, B1, B1, [3]
Part (iii):
AnswerMarks Guidance
AnswerMark Guidance
Large positive \(x\), \(y \to 2^-\) (e.g. consider \(x = 100\))B1 Evidence of method needed for this mark
Large negative \(x\), \(y \to 2^+\) (e.g. consider \(x = -100\))B1, B1, [3]
Part (iv):
AnswerMarks Guidance
AnswerMark Guidance
Curve: 3 branchesB1 Consistent with their (iii)
Asymptotes markedB1
Correctly located and no extra interceptsB1, [3]
Part (v):
AnswerMarks Guidance
AnswerMark Guidance
\(y = 2 \Rightarrow 2 = \frac{(2x-3)(x+1)}{(x+4)(x-2)}\)M1 Some attempt at rearrangement
\(\Rightarrow 2x^2 + 4x - 16 = 2x^2 - x - 3\)
\(\Rightarrow x = \frac{13}{5}\)A1 May be given retrospectively
From sketch, \(y \leq 2\) for \(x \geq \frac{13}{5}\) or \(2 > x > -4\)A1, B1, [4] B1 for \(2 > x > -4\)
# Question 7:

## Part (i):
| Answer | Mark | Guidance |
|--------|------|----------|
| $x = \frac{3}{2}$ and $-1$ | B1, **[1]** | Both |

## Part (ii):
| Answer | Mark | Guidance |
|--------|------|----------|
| $x = 2$, $x = -4$ and $y = 2$ | B1, B1, B1, **[3]** | |

## Part (iii):
| Answer | Mark | Guidance |
|--------|------|----------|
| Large positive $x$, $y \to 2^-$ (e.g. consider $x = 100$) | B1 | Evidence of method needed for this mark |
| Large negative $x$, $y \to 2^+$ (e.g. consider $x = -100$) | B1, B1, **[3]** | |

## Part (iv):
| Answer | Mark | Guidance |
|--------|------|----------|
| Curve: 3 branches | B1 | Consistent with their (iii) |
| Asymptotes marked | B1 | |
| Correctly located and no extra intercepts | B1, **[3]** | |

## Part (v):
| Answer | Mark | Guidance |
|--------|------|----------|
| $y = 2 \Rightarrow 2 = \frac{(2x-3)(x+1)}{(x+4)(x-2)}$ | M1 | Some attempt at rearrangement |
| $\Rightarrow 2x^2 + 4x - 16 = 2x^2 - x - 3$ | | |
| $\Rightarrow x = \frac{13}{5}$ | A1 | May be given retrospectively |
| From sketch, $y \leq 2$ for $x \geq \frac{13}{5}$ or $2 > x > -4$ | A1, B1, **[4]** | B1 for $2 > x > -4$ |

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7 A curve has equation $y = \frac { ( 2 x - 3 ) ( x + 1 ) } { ( x + 4 ) ( x - 2 ) }$.
\begin{enumerate}[label=(\roman*)]
\item Write down the values of $x$ for which $y = 0$.
\item Write down the equations of the three asymptotes.
\item Determine whether the curve approaches the horizontal asymptote from above or from below for\\
(A) large positive values of $x$,\\
(B) large negative values of $x$.
\item Sketch the curve.
\item Solve the inequality $\frac { ( 2 x - 3 ) ( x + 1 ) } { ( x + 4 ) ( x - 2 ) } \leqslant 2$.
\end{enumerate}

\hfill \mbox{\textit{OCR MEI FP1 2005 Q7 [14]}}