Finding quadratic from vertex information

Questions where the vertex coordinates and another point are given, requiring construction of the quadratic function in vertex form then possibly expanding.

3 questions

Edexcel P1 2024 January Q9
  1. The curve \(C _ { 1 }\) has equation \(y = \mathrm { f } ( x )\).
Given that
  • \(\mathrm { f } ( x )\) is a quadratic expression
  • \(C _ { 1 }\) has a maximum turning point at \(( 2,20 )\)
  • \(C _ { 1 }\) passes through the origin
    1. sketch a graph of \(C _ { 1 }\) showing the coordinates of any points where \(C _ { 1 }\) cuts the coordinate axes,
    2. find an expression for \(\mathrm { f } ( x )\).
The curve \(C _ { 2 }\) has equation \(y = x \left( x ^ { 2 } - 4 \right)\)
Curve \(C _ { 1 }\) and \(C _ { 2 }\) meet at the origin, and at the points \(P\) and \(Q\)
Given that the \(x\) coordinate of the point \(P\) is negative,
  • using algebra and showing all stages of your working, find the coordinates of \(P\)
  • Edexcel P1 2022 June Q5
    1. The curve \(C\) has equation \(y = \mathrm { f } ( x )\)
    Given that
    • \(\mathrm { f } ( x )\) is a quadratic expression
    • the maximum turning point on \(C\) has coordinates \(( - 2,12 )\)
    • \(C\) cuts the negative \(x\)-axis at - 5
      1. find \(\mathrm { f } ( x )\)
    The line \(l _ { 1 }\) has equation \(y = \frac { 4 } { 5 } x\) Given that the line \(l _ { 2 }\) is perpendicular to \(l _ { 1 }\) and passes through \(( - 5,0 )\)
  • find an equation for \(l _ { 2 }\), writing your answer in the form \(y = m x + c\) where \(m\) and \(c\) are constants to be found.
    (3) \begin{figure}[h]
    \includegraphics[alt={},max width=\textwidth]{3cf69966-e825-4ff0-a6e8-c5dfdc92c53f-10_983_712_1126_616} \captionsetup{labelformat=empty} \caption{Figure 2}
    \end{figure} Figure 2 shows a sketch of the curve \(C\) and the lines \(l _ { 1 }\) and \(l _ { 2 }\)
  • Define the region \(R\), shown shaded in Figure 2, using inequalities.
  • SPS SPS SM Pure 2024 September Q6
    1. The curve \(C _ { 1 }\) has equation \(y = \mathrm { f } ( x )\).
    Given that
    • \(\mathrm { f } ( x )\) is a quadratic expression
    • \(C _ { 1 }\) has a maximum turning point at \(( 2,20 )\)
    • \(C _ { 1 }\) passes through the origin
      1. sketch a graph of \(C _ { 1 }\) showing the coordinates of any points where \(C _ { 1 }\) cuts the coordinate axes,
      2. find an expression for \(\mathrm { f } ( x )\).
    The curve \(C _ { 2 }\) has equation \(y = x \left( x ^ { 2 } - 4 \right)\)
    Curve \(C _ { 1 }\) and \(C _ { 2 }\) meet at the origin, and at the points \(P\) and \(Q\)
    Given that the \(x\) coordinate of the point \(P\) is negative,
  • using algebra and showing all stages of your working, find the coordinates of \(P\)
    (3)