Edexcel C4 — Question 3

Exam BoardEdexcel
ModuleC4 (Core Mathematics 4)
TopicImplicit equations and differentiation

  1. A curve has the equation
$$2 \sin 2 x - \tan y = 0$$
  1. Find an expression for \(\frac { \mathrm { d } y } { \mathrm {~d} x }\) in its simplest form in terms of \(x\) and \(y\).
  2. Show that the tangent to the curve at the point \(\left( \frac { \pi } { 6 } , \frac { \pi } { 3 } \right)\) has the equation $$y = \frac { 1 } { 2 } x + \frac { \pi } { 4 }$$
    1. continued
    \begin{figure}[h]
    \includegraphics[alt={},max width=\textwidth]{3cf64017-e982-4165-9885-8524aaabdf84-06_433_812_246_479} \captionsetup{labelformat=empty} \caption{Figure 1}
    \end{figure} Figure 1 shows the curve with parametric equations $$x = a \sqrt { t } , \quad y = a t ( 1 - t ) , \quad t \geq 0$$ where \(a\) is a positive constant.
  3. Find \(\frac { \mathrm { d } y } { \mathrm {~d} x }\) in terms of \(t\). The curve meets the \(x\)-axis at the origin, \(O\), and at the point \(A\). The tangent to the curve at \(A\) meets the \(y\)-axis at the point \(B\) as shown.
  4. Show that the area of triangle \(O A B\) is \(a ^ { 2 }\).