| Exam Board | AQA |
|---|---|
| Module | Paper 2 (Paper 2) |
| Session | Specimen |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Parametric curves and Cartesian conversion |
| Type | Find dy/dx at a point |
| Difficulty | Moderate -0.3 Part (a) requires standard application of the parametric differentiation formula dy/dx = (dy/dt)/(dx/dt) with straightforward polynomial derivatives. Part (b) involves eliminating the parameter by expressing t from one equation and substituting—a routine technique. Both parts are textbook exercises requiring recall of standard methods with minimal problem-solving, making this slightly easier than average. |
| Spec | 1.03g Parametric equations: of curves and conversion to cartesian1.07s Parametric and implicit differentiation |
| Answer | Marks |
|---|---|
| 3(a) | Uses a correct method for finding |
| Answer | Marks | Guidance |
|---|---|---|
| part (b) | AO1.1a | M1 |
| Answer | Marks | Guidance |
|---|---|---|
| dx | AO1.1b | A1 |
| Answer | Marks | Guidance |
|---|---|---|
| dx | AO1.1a | M1 |
| Answer | Marks | Guidance |
|---|---|---|
| dx | AO1.1b | A1F |
| (b) | Eliminates t or makes t the subject in |
| Answer | Marks | Guidance |
|---|---|---|
| equations with equal powers of t.) | AO1.1a | M1 |
| Answer | Marks | Guidance |
|---|---|---|
| any form | AO1.1b | A1 |
| Total | 6 | |
| Q | Marking Instructions | AO |
Question 3:
--- 3(a) ---
3(a) | Uses a correct method for finding
dy
dx
evidence for this includes sight of
dy dx
or and chain rule
dx dt
OR an attempt at implicit or explicit
differentiation of a correct Cartesian
equation or ‘their’ equation from
part (b) | AO1.1a | M1 | dx dy
3t2 2t
dt dt
dy 2t
dx 3t2
dy 1
When t 2
dx 3
ALT
2
y(x2)3 1
1
dy 2(x2) 3
dx 3
When t = –2 , x = –6
1
dy 2(62) 3 1
dx 3 3
dy
Obtains correct
dx | AO1.1b | A1
Substitutes t = –2 (or x = –6) into
dy
‘their’ equation for
dx | AO1.1a | M1
Obtains correct simplified gradient of
the curve
dy
FT ‘their’ equation for
dx | AO1.1b | A1F
(b) | Eliminates t or makes t the subject in
one expression
(evidence for this includes one
equation with t as the subject or two
equations with equal powers of t.) | AO1.1a | M1 | t3 (x2), t2 (y1)
t6 (x2)2, t6 (y1)3
(x2)2 (y1)3
ALT
t3 (x2)
1
t (x2)3
2
y(x2)3 1
Finds a correct Cartesian equation in
any form | AO1.1b | A1
Total | 6
Q | Marking Instructions | AO | Marks | Typical Solution
A curve is defined by the parametric equations
$$x = t^3 + 2, \quad y = t^2 - 1$$
\begin{enumerate}[label=(\alph*)]
\item Find the gradient of the curve at the point where $t = -2$
[4 marks]
\item Find a Cartesian equation of the curve.
[2 marks]
\end{enumerate}
\hfill \mbox{\textit{AQA Paper 2 Q3 [6]}}