Sketch with inequalities or regions

Questions asking to sketch a factored polynomial curve and then use the sketch to solve inequalities or identify solution regions.

4 questions

OCR H240/01 2018 June Q6
6 The cubic polynomial \(\mathrm { f } ( x )\) is defined by \(\mathrm { f } ( x ) = 2 x ^ { 3 } - 7 x ^ { 2 } + 2 x + 3\).
  1. Given that ( \(x - 3\) ) is a factor of \(\mathrm { f } ( x )\), express \(\mathrm { f } ( x )\) in a fully factorised form.
  2. Sketch the graph of \(y = \mathrm { f } ( x )\), indicating the coordinates of any points of intersection with the axes.
  3. Solve the inequality \(\mathrm { f } ( x ) < 0\), giving your answer in set notation.
  4. The graph of \(y = \mathrm { f } ( x )\) is transformed by a stretch parallel to the \(x\)-axis, scale factor \(\frac { 1 } { 2 }\). Find the equation of the transformed graph.
Edexcel AS Paper 1 2022 June Q7
  1. (a) Factorise completely \(9 x - x ^ { 3 }\)
The curve \(C\) has equation $$y = 9 x - x ^ { 3 }$$ (b) Sketch \(C\) showing the coordinates of the points at which the curve cuts the \(x\)-axis. The line \(l\) has equation \(y = k\) where \(k\) is a constant.
Given that \(C\) and \(l\) intersect at 3 distinct points,
(c) find the range of values for \(k\), writing your answer in set notation. Solutions relying on calculator technology are not acceptable.
AQA AS Paper 1 2019 June Q5
5
  1. Sketch the curve \(y = \mathrm { g } ( x )\) where $$g ( x ) = ( x + 2 ) ( x - 1 ) ^ { 2 }$$ 5
  2. Hence, solve \(\mathrm { g } ( x ) \leq 0\)
AQA AS Paper 1 2021 June Q5
5
  1. Sketch the curve $$y = ( x - a ) ^ { 2 } ( 3 - x ) \quad \text { where } 0 < a < 3$$ indicating the coordinates of the points where the curve and the axes meet.
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  2. Hence, solve $$( x - a ) ^ { 2 } ( 3 - x ) > 0$$ giving your answer in set notation form.