2.62: Stationary points on a cubic composite curve

0606/23/M/J/19 — Question 6 · 8 marks

A curve has equation y=(3x5)32xy = (3x - 5)^{3} - 2x.
(i)
Find dydx\dfrac{\mathrm{d}y}{\mathrm{d}x} and d2ydx2\dfrac{\mathrm{d}^{2}y}{\mathrm{d}x^{2}}.
[4]
(ii)
Find the exact value of the xx-coordinate of each of the stationary points of the curve.
[2]
(iii)
Use the second derivative test to determine the nature of each of the stationary points.
[2]