Edexcel F2 2024 January — Question 1 5 marks

Exam BoardEdexcel
ModuleF2 (Further Pure Mathematics 2)
Year2024
SessionJanuary
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicInequalities
TypeRational inequality algebraically
DifficultyModerate -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.
Spec1.02g Inequalities: linear and quadratic in single variable1.02k Simplify rational expressions: factorising, cancelling, algebraic division

  1. Using algebra, solve the inequality
$$\frac { 1 } { x + 2 } > 2 x + 3$$

Question 1:
\[\frac{1}{x+2} > 2x+3\]
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 \(\frac{1}{x+2}=2x+3 \Rightarrow (2x+3)(x+2)-1=2x^2+7x+5=0\)
AnswerMarks
M1Uses 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).
Step 2 – Critical values from quadratic:
\(x = -\frac{5}{2}, -1\)
AnswerMarks
A1Both \(-1\) and \(-\frac{5}{2}\) from appropriate work, no extra incorrect critical values. May only appear in solution set. Allow solving 3TQ by calculator.
Step 3 – Critical value \(x=-2\):
\(x=-2\)
AnswerMarks
B1Identifies \(-2\) as a critical value. May only appear in solution set. This mark available even if no algebraic manipulation seen. Allow from e.g., \((2x+3)(x+2)=0\).
Step 4 – Final solution set:
\(x < -\frac{5}{2},\ -2 < x < -1\)
or e.g., \(\left(-\infty, -2.5\right),\left(-2,-1\right)\)
AnswerMarks
M1 A1M1: Regions \(x-2\) (condone \(bA1: 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.
Total: (5)
# Question 1:

$$\frac{1}{x+2} > 2x+3$$

---

**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). |

---

**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. |

---

**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., $(2x+3)(x+2)=0$. |

---

**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. |

---

**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]}}