Edexcel P1 2021 October — Question 4

Exam BoardEdexcel
ModuleP1 (Pure Mathematics 1)
Year2021
SessionOctober
TopicTrig Graphs & Exact Values

4. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{f1e1d4f5-dd27-4839-a6f3-f6906666302c-08_721_855_214_550} \captionsetup{labelformat=empty} \caption{Figure 2}
\end{figure} Figure 2 shows a sketch of the curve with equation \(y = \mathrm { f } ( x )\), where $$f ( x ) = \cos 2 x ^ { \circ } \quad 0 \leqslant x \leqslant k$$ The point \(Q\) and the point \(R ( k , 0 )\) lie on the curve and are shown in Figure 2.
  1. State
    1. the coordinates of \(Q\),
    2. the value of \(k\).
  2. Given that there are exactly two solutions to the equation $$\cos 2 x ^ { \circ } = p \quad \text { in the region } 0 \leqslant x \leqslant k$$ find the range of possible values for \(p\).