Rational curve analysis with turning points and range restrictions

Prove existence or non-existence of turning points (using calculus or discriminant), show that y is restricted to certain ranges, and sketch the curve.

8 questions · Standard +0.7

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CAIE FP1 2014 June Q11 EITHER
Standard +0.8
Express \(\frac { 2 x ^ { 2 } - x + 5 } { x ^ { 2 } - 1 }\) in the form \(2 + \frac { A } { x - 1 } + \frac { B } { x + 1 }\), where \(A\) and \(B\) are integers to be found. The curve \(C\) has equation \(y = \frac { 2 x ^ { 2 } - x + 5 } { x ^ { 2 } - 1 }\). Show that there are two distinct values of \(x\) for which \(\frac { \mathrm { d } y } { \mathrm {~d} x } = 0\). Sketch \(C\), stating the equations of the asymptotes and giving the coordinates of any points of intersection with the coordinate axes and with the asymptotes. You do not need to find the coordinates of the turning points.
CAIE FP1 2017 November Q9
12 marks Standard +0.8
9 The curve \(C\) has equation $$y = \frac { 3 x - 9 } { ( x - 2 ) ( x + 1 ) }$$
  1. Find the equations of the asymptotes of \(C\). \includegraphics[max width=\textwidth, alt={}, center]{9221f480-4af6-44be-a535-d2ceb0f8b5d2-14_61_1566_513_328}
  2. Show that there is no point on \(C\) for which \(\frac { 1 } { 3 } < y < 3\).
  3. Find the coordinates of the turning points of \(C\).
  4. Sketch \(C\).
CAIE FP1 2017 November Q9
12 marks Standard +0.3
9 The curve \(C\) has equation $$y = \frac { 3 x - 9 } { ( x - 2 ) ( x + 1 ) }$$
  1. Find the equations of the asymptotes of \(C\). \includegraphics[max width=\textwidth, alt={}, center]{a0987277-06e9-451b-ae18-bb7de9e7661c-14_61_1566_513_328}
  2. Show that there is no point on \(C\) for which \(\frac { 1 } { 3 } < y < 3\).
  3. Find the coordinates of the turning points of \(C\).
  4. Sketch \(C\).
CAIE FP1 2015 June Q10
11 marks Standard +0.8
10 The curve \(C\) has equation \(y = \frac { 4 x ^ { 2 } - 3 x } { x ^ { 2 } + 1 }\). Verify that the equation of \(C\) may be written in the form \(y = - \frac { 1 } { 2 } + \frac { ( 3 x - 1 ) ^ { 2 } } { 2 \left( x ^ { 2 } + 1 \right) }\) and also in the form \(y = \frac { 9 } { 2 } - \frac { ( x + 3 ) ^ { 2 } } { 2 \left( x ^ { 2 } + 1 \right) }\). Hence show that \(- \frac { 1 } { 2 } \leqslant y \leqslant \frac { 9 } { 2 }\). Without differentiating, write down the coordinates of the turning points of \(C\). State the equation of the asymptote of \(C\). Sketch the graph of \(C\), stating the coordinates of the intersections with the coordinate axes and the asymptote.
AQA Further AS Paper 1 2023 June Q10
9 marks Standard +0.3
10
  1. Write down the equation of the horizontal asymptote of \(C\) 10
  2. Find the value of \(m\) and the value of \(p\)
    10
  3. 10
  4. Hence, or otherwise, write down the coordinates of the \(y\)-intercept of \(C\)
    Without using calculus, show that the line \(y = - 1\) does not intersect \(C\)
AQA FP1 2011 January Q7
15 marks Standard +0.8
7 A graph has equation $$y = \frac { x - 4 } { x ^ { 2 } + 9 }$$
  1. Explain why the graph has no vertical asymptote and give the equation of the horizontal asymptote.
  2. Show that, if the line \(y = k\) intersects the graph, the \(x\)-coordinates of the points of intersection of the line with the graph must satisfy the equation $$k x ^ { 2 } - x + ( 9 k + 4 ) = 0$$
  3. Show that this equation has real roots if \(- \frac { 1 } { 2 } \leqslant k \leqslant \frac { 1 } { 18 }\).
  4. Hence find the coordinates of the two stationary points on the curve.
    (No credit will be given for methods involving differentiation.)
AQA FP1 2009 June Q8
15 marks Standard +0.8
8 A curve has equation $$y = \frac { x ^ { 2 } } { ( x - 1 ) ( x - 5 ) }$$
  1. Write down the equations of the three asymptotes to the curve.
  2. Show that the curve has no point of intersection with the line \(y = - 1\).
    1. Show that, if the curve intersects the line \(y = k\), then the \(x\)-coordinates of the points of intersection must satisfy the equation $$( k - 1 ) x ^ { 2 } - 6 k x + 5 k = 0$$
    2. Show that, if this equation has equal roots, then $$k ( 4 k + 5 ) = 0$$
  3. Hence find the coordinates of the two stationary points on the curve.
AQA Further AS Paper 1 2019 June Q11
8 marks Challenging +1.2
  1. Curve \(C\) has equation $$y = \frac{x^2 + px - q}{x^2 - r}$$ where \(p\), \(q\) and \(r\) are positive constants. Write down the equations of its asymptotes. [2 marks]
  2. Find the set of possible \(y\)-coordinates for the graph of $$y = \frac{x^2 + x - 6}{x^2 - 1}, \quad x \neq \pm 1$$ giving your answer in exact form. No credit will be given for solutions based on differentiation. [6 marks]