Edexcel P1 2019 October — Question 10

Exam BoardEdexcel
ModuleP1 (Pure Mathematics 1)
Year2019
SessionOctober
TopicCurve Sketching
TypeDeduce inequality solutions from sketch

10. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{50ec901b-b6b6-4b72-85bd-a084f313c99b-22_592_665_251_676} \captionsetup{labelformat=empty} \caption{Figure 6}
\end{figure} Figure 6 shows a sketch of part of the curve with equation \(y = \mathrm { f } ( x )\), where $$f ( x ) = ( 2 x + 5 ) ( x - 3 ) ^ { 2 }$$
  1. Deduce the values of \(x\) for which \(\mathrm { f } ( x ) \leqslant 0\) The curve crosses the \(y\)-axis at the point \(P\), as shown.
  2. Expand \(\mathrm { f } ( x )\) to the form $$a x ^ { 3 } + b x ^ { 2 } + c x + d$$ where \(a\), \(b\), \(c\) and \(d\) are integers to be found.
  3. Hence, or otherwise, find
    1. the coordinates of \(P\),
    2. the gradient of the curve at \(P\). The curve with equation \(y = \mathrm { f } ( x )\) is translated two units in the positive \(x\) direction to a curve with equation \(y = \mathrm { g } ( x )\).
    1. Find \(\mathrm { g } ( x )\), giving your answer in a simplified factorised form.
    2. Hence state the \(y\) intercept of the curve with equation \(y = \mathrm { g } ( x )\).