Challenging +1.2 This question requires implicit differentiation of a composite function involving an exponential, then solving the resulting system to find stationary points. While it combines several techniques (chain rule, implicit differentiation, exponential functions), the approach is methodical and the algebra, though careful, follows standard patterns. It's moderately harder than average due to the implicit nature and multi-step solving required, but doesn't demand unusual insight.
Question 6:
6 | Selects appropriate technique to
differentiate | AO3.1a | M1 | dy dy
2x y2 1 ey
dx dx
dy
0 x y20
dx
0ey 1
y 0
x2
Differentiates term involving ey
correctly | AO1.1b | B1
Differentiates fully correctly | AO1.1b | A1
dy
Uses 0
dx | AO1.1a | M1
Eliminates x or y from the equation
of the curve | AO1.1a | M1
Obtains correct y CAO | AO1.1b | A1
Obtains correct x CAO | AO1.1b | A1
Total | 7
Q | Marking Instructions | AO | Marks | Typical Solution
Find the coordinates of the stationary point of the curve with equation
$(x + y - 2)^2 = e^y - 1$
[7 marks]
\hfill \mbox{\textit{AQA Paper 2 2018 Q6 [7]}}