Edexcel P3 2023 January — Question 7

Exam BoardEdexcel
ModuleP3 (Pure Mathematics 3)
Year2023
SessionJanuary
TopicImplicit equations and differentiation

  1. The curve \(C\) has equation
$$x = 3 \tan \left( y - \frac { \pi } { 6 } \right) \quad x \in \mathbb { R } \quad - \frac { \pi } { 3 } < y < \frac { 2 \pi } { 3 }$$
  1. Show that $$\frac { \mathrm { d } y } { \mathrm {~d} x } = \frac { a } { x ^ { 2 } + b }$$ where \(a\) and \(b\) are integers to be found. The point \(P\) with \(y\) coordinate \(\frac { \pi } { 3 }\) lies on \(C\).
    Given that the tangent to \(C\) at \(P\) crosses the \(x\)-axis at the point \(Q\).
  2. find, in simplest form, the exact \(x\) coordinate of \(Q\).