7.
\begin{figure}[h]
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\caption{Figure 2}
\includegraphics[alt={},max width=\textwidth]{e4d38009-aa70-4c55-9765-c54044ffaa31-3_771_972_1322_557}
\end{figure}
Fig. 2 shows part of the curve \(C\) with equation \(y = \mathrm { f } ( x )\), where \(\mathrm { f } ( x ) = x ^ { 3 } - 6 x ^ { 2 } + 5 x\).
The curve crosses the \(x\)-axis at the origin \(O\) and at the points \(A\) and \(B\).
- Factorise \(\mathrm { f } ( x )\) completely.
- Write down the \(x\)-coordinates of the points \(A\) and \(B\).
- Find the gradient of \(C\) at \(A\).
The region \(R\) is bounded by \(C\) and the line \(O A\), and the region \(S\) is bounded by \(C\) and the line \(A B\).
- Use integration to find the area of the combined regions \(R\) and \(S\), shown shaded in Fig.2.
\begin{figure}[h]
\captionsetup{labelformat=empty}
\caption{Figure 3}
\includegraphics[alt={},max width=\textwidth]{e4d38009-aa70-4c55-9765-c54044ffaa31-4_736_727_338_402}
\end{figure}
Fig. 3 shows a sketch of part of the curve \(C\) with equation \(y = x ^ { 3 } - 7 x ^ { 2 } + 15 x + 3 , x \geq 0\). The point \(P\), on \(C\), has \(x\)-coordinate 1 and the point \(Q\) is the minimum turning point of \(C\). - Find \(\frac { \mathrm { d } y } { \mathrm {~d} x }\).
- Find the coordinates of \(Q\).
- Show that \(P Q\) is parallel to the \(x\)-axis.
- Calculate the area, shown shaded in Fig. 3, bounded by \(C\) and the line \(P Q\).