2023 RI P1 Q9

2023 RI P1 Q9

Junior College 1
10 marks

The curve \(C\) has equation

\(y = \frac{ax^2 + x}{x + b},\)

where \(a\) and \(b\) are positive constants such that \(a \neq \frac{1}{b}\).

  1. Given that \(C\) has no stationary points, use differentiation to find the relationship between \(a\) and \(b\).[4]

It is now given that \(a = 2\) and \(b = 1\).

  1. Sketch \(C\), stating the equations of any asymptotes, coordinates of any turning points and of the points where \(C\) crosses the axes.[4]
  2. Hence find the volume of the solid formed when the finite region bounded by \(C\) and the \(x\)-axis is rotated completely about the \(x\)-axis.[2]
Similar questions are unavailable for this question.
Answer:(a) \({0 < ab < 1}\) (b) \({x = -1}\), \({y = 2x - 1}\) ; Turning points \({= (-0.293, -0.172)}\) ; \({(0, 0)}\), \({\left(-\frac{1}{2}, 0\right)}\), \({(-1.71, -5.83)}\) (c) \({0.0245}\) (\(3\) s.f.)

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