Edexcel C4 2014 June — Question 8

Exam BoardEdexcel
ModuleC4 (Core Mathematics 4)
Year2014
SessionJune
TopicParametric equations

8. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{e14881c1-5ba5-4868-92ee-8bc58d4884dc-13_808_965_248_502} \captionsetup{labelformat=empty} \caption{Figure 3}
\end{figure} The curve shown in Figure 3 has parametric equations $$x = t - 4 \sin t , y = 1 - 2 \cos t , \quad - \frac { 2 \pi } { 3 } \leqslant t \leqslant \frac { 2 \pi } { 3 }$$ The point \(A\), with coordinates ( \(k , 1\) ), lies on the curve. Given that \(k > 0\)
  1. find the exact value of \(k\),
  2. find the gradient of the curve at the point \(A\). There is one point on the curve where the gradient is equal to \(- \frac { 1 } { 2 }\)
  3. Find the value of \(t\) at this point, showing each step in your working and giving your answer to 4 decimal places.
    [0pt] [Solutions based entirely on graphical or numerical methods are not acceptable.]