Edexcel Paper 1 2018 June — Question 6

Exam BoardEdexcel
ModulePaper 1 (Paper 1)
Year2018
SessionJune
TopicCircles

6. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{b5f50f17-9f1b-4b4c-baf3-e50de5f2ea9c-12_549_592_244_731} \captionsetup{labelformat=empty} \caption{Figure 3}
\end{figure} Not to scale The circle \(C\) has centre \(A\) with coordinates (7,5).
The line \(l\), with equation \(y = 2 x + 1\), is the tangent to \(C\) at the point \(P\), as shown in Figure 3 .
  1. Show that an equation of the line \(P A\) is \(2 y + x = 17\)
  2. Find an equation for \(C\). The line with equation \(y = 2 x + k , \quad k \neq 1\) is also a tangent to \(C\).
  3. Find the value of the constant \(k\).