6.
\begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{129adfbb-98fa-4e88-b636-7b4d111f3349-12_528_812_251_628}
\captionsetup{labelformat=empty}
\caption{Figure 1}
\end{figure}
Figure 1 shows a sketch of a curve \(C\) with equation \(y = \mathrm { f } ( x )\) where \(\mathrm { f } ( x )\) is a cubic expression in \(X\).
The curve
- passes through the origin
- has a maximum turning point at \(( 2,8 )\)
- has a minimum turning point at \(( 6,0 )\)
- Write down the set of values of \(x\) for which
$$\mathrm { f } ^ { \prime } ( x ) < 0$$
The line with equation \(y = k\), where \(k\) is a constant, intersects \(C\) at only one point.
Find the set of values of \(k\), giving your answer in set notation.Find the equation of \(C\). You may leave your answer in factorised form.