OCR MEI C3 2012 January — Question 7

Exam BoardOCR MEI
ModuleC3 (Core Mathematics 3)
Year2012
SessionJanuary
TopicImplicit equations and differentiation

7 Fig. 7 shows the curve \(x ^ { 3 } + y ^ { 3 } = 3 x y\). The point P is a turning point of the curve. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{8b8958be-0ebc-4f72-ac3f-c16a8ec9e4ab-3_583_513_708_776} \captionsetup{labelformat=empty} \caption{Fig. 7}
\end{figure}
  1. Show that \(\frac { \mathrm { d } y } { \mathrm {~d} x } = \frac { y - x ^ { 2 } } { y ^ { 2 } - x }\).
  2. Hence find the exact \(x\)-coordinate of P . Section B (36 marks)