Edexcel Paper 2 2021 October — Question 8

Exam BoardEdexcel
ModulePaper 2 (Paper 2)
Year2021
SessionOctober
TopicImplicit equations and differentiation

  1. The curve \(C\) has equation
$$p x ^ { 3 } + q x y + 3 y ^ { 2 } = 26$$ where \(p\) and \(q\) are constants.
  1. Show that $$\frac { \mathrm { d } y } { \mathrm {~d} x } = \frac { a p x ^ { 2 } + b q y } { q x + c y }$$ where \(a\), \(b\) and \(c\) are integers to be found. Given that
    • the point \(P ( - 1 , - 4 )\) lies on \(C\)
    • the normal to \(C\) at \(P\) has equation \(19 x + 26 y + 123 = 0\)
    • find the value of \(p\) and the value of \(q\).