| Exam Board | Edexcel |
|---|---|
| Module | F2 (Further Pure Mathematics 2) |
| Year | 2024 |
| Session | January |
| Marks | 5 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Inequalities |
| Type | Rational inequality algebraically |
| Difficulty | Moderate -0.3 This is a straightforward rational inequality requiring standard algebraic manipulation: rearrange to single fraction, find critical points from numerator and denominator, and test intervals. While it requires care with sign changes and domain restrictions, it's a routine Further Maths technique with no conceptual surprises, making it slightly easier than average. |
| Spec | 1.02g Inequalities: linear and quadratic in single variable1.02k Simplify rational expressions: factorising, cancelling, algebraic division |
| Answer | Marks |
|---|---|
| M1 | Uses algebra to obtain a 3TQ, \((x+2)\) multiplied by a 3TQ or a 4TC. Allow slips and condone incorrect inequality signs but the first algebraic step should be otherwise appropriate. Do not accept e.g., \((2x+3)(x+2)=0\). Squaring first acceptable (obtaining a 5TQ). |
| Answer | Marks |
|---|---|
| A1 | Both \(-1\) and \(-\frac{5}{2}\) from appropriate work, no extra incorrect critical values. May only appear in solution set. Allow solving 3TQ by calculator. |
| Answer | Marks |
|---|---|
| B1 | Identifies \(-2\) as a critical value. May only appear in solution set. This mark available even if no algebraic manipulation seen. Allow from e.g., \((2x+3)(x+2)=0\). |
# Question 1:
$$\frac{1}{x+2} > 2x+3$$
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**Step 1 – Algebraic manipulation to obtain a 3TQ or 4TC:**
$\frac{1-(x+2)(2x+3)}{x+2} > 0 \Rightarrow 2x^2+7x+5=0$
or $x+2>(2x+3)(x+2)^2$
or $\frac{1}{x+2}=2x+3 \Rightarrow (2x+3)(x+2)-1=2x^2+7x+5=0$
| M1 | Uses algebra to obtain a 3TQ, $(x+2)$ multiplied by a 3TQ or a 4TC. Allow slips and condone incorrect inequality signs but the first algebraic step should be otherwise appropriate. Do not accept e.g., $(2x+3)(x+2)=0$. Squaring first acceptable (obtaining a 5TQ). |
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**Step 2 – Critical values from quadratic:**
$x = -\frac{5}{2}, -1$
| A1 | Both $-1$ and $-\frac{5}{2}$ from appropriate work, no extra incorrect critical values. May only appear in solution set. Allow solving 3TQ by calculator. |
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**Step 3 – Critical value $x=-2$:**
$x=-2$
| B1 | Identifies $-2$ as a critical value. May only appear in solution set. This mark available even if no algebraic manipulation seen. Allow from e.g., $(2x+3)(x+2)=0$. |
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**Step 4 – Final solution set:**
$x < -\frac{5}{2},\ -2 < x < -1$
or e.g., $\left(-\infty, -2.5\right),\left(-2,-1\right)$
| M1 A1 | **M1**: Regions $x<a$, $-2<x<b$ with real cvs $a<-2$ and $b>-2$ (condone $b<x<-2$ as notational slip). Condone non-strict inequalities and poor notation. Not dependent but must follow algebraic manipulation attempt. **A1**: Correct solution set in any form. Do not isw if correct inequalities subsequently incorrectly amended. Allow all marks even if incorrect inequality sign seen earlier. |
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**Total: (5)**
\begin{enumerate}
\item Using algebra, solve the inequality
\end{enumerate}
$$\frac { 1 } { x + 2 } > 2 x + 3$$
\hfill \mbox{\textit{Edexcel F2 2024 Q1 [5]}}