| Exam Board | AQA |
|---|---|
| Module | Paper 1 (Paper 1) |
| Session | Specimen |
| Marks | 8 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Radians, Arc Length and Sector Area |
| Type | Simultaneous equations with arc/area |
| Difficulty | Moderate -0.3 This is a straightforward sector problem requiring standard formulas (area = ½r²θ, perimeter = 2r + rθ) and solving a quadratic equation. Part (a) is algebraic manipulation following clear steps, and part (b) requires checking which root gives a valid angle. While it tests multiple concepts, the approach is routine with no novel insight required, making it slightly easier than average. |
| Spec | 1.05d Radians: arc length s=r*theta and sector area A=1/2 r^2 theta |
| Answer | Marks |
|---|---|
| 5(a) | 1 |
| Answer | Marks | Guidance |
|---|---|---|
| PI by use in equation | AO1.2 | B1 |
| Answer | Marks | Guidance |
|---|---|---|
| least one correct | AO1.1a | M1 |
| Answer | Marks | Guidance |
|---|---|---|
| FT incorrect equations | AO1.1a | M1 |
| Answer | Marks | Guidance |
|---|---|---|
| eliminating AG | AO2.1 | R1 |
| (b) | Solves a quadratic equation | |
| and finds two values of | AO3.1a | M1 |
| Answer | Marks | Guidance |
|---|---|---|
| Finds two correct values of r | AO1.1b | B1 |
| Finds both values of | AO1.1b | A1 |
| Answer | Marks | Guidance |
|---|---|---|
| rejecting one of ‘their’ values | AO2.4 | R1 |
| Total | 8 | |
| Q | Marking Instructions | AO |
Question 5:
--- 5(a) ---
5(a) | 1
Recalls A r2 or l r
2
PI by use in equation | AO1.2 | B1 | Area of sector gives
1 18
r29,
2 r2
Perimeter of sector gives
2rr15
18
2r 15
r
2r2 1815r
2r215r180 (AG)
Constructs two equations at
least one correct | AO1.1a | M1
Eliminates
FT incorrect equations | AO1.1a | M1
Constructs a rigorous
mathematical argument to
show required result, clearly
constructing two correct
simultaneous equations and
eliminating AG | AO2.1 | R1
(b) | Solves a quadratic equation
and finds two values of | AO3.1a | M1 | 3
r ,r 6
2
1
r 6
2
3
r 8
2
828
so only one possible value of
Finds two correct values of r | AO1.1b | B1
Finds both values of | AO1.1b | A1
Gives a valid reason for
rejecting one of ‘their’ values | AO2.4 | R1
Total | 8
Q | Marking Instructions | AO | Marks | Typical Solution
The diagram shows a sector $AOB$ of a circle with centre $O$ and radius $r$ cm.
\includegraphics{figure_5}
The angle $AOB$ is $\theta$ radians
The sector has area 9 cm$^2$ and perimeter 15 cm.
\begin{enumerate}[label=(\alph*)]
\item Show that $r$ satisfies the equation $2r^2 - 15r + 18 = 0$
[4 marks]
\item Find the value of $\theta$. Explain why it is the only possible value.
[4 marks]
\end{enumerate}
\hfill \mbox{\textit{AQA Paper 1 Q5 [8]}}