Edexcel PURE 2024 October — Question 7

Exam BoardEdexcel
ModulePURE
Year2024
SessionOctober
PaperDownload PDF ↗
TopicTrig Graphs & Exact Values
TypeFind coordinates of turning points
DifficultyEasy -1.2 This question tests basic properties of cosine graphs through straightforward reading of coordinates from a graph and simple transformations. Parts (a) and (b) require only recall of cosine graph properties (max/min values, period), while part (c) involves counting intersections visually—all standard textbook exercises with no problem-solving or novel insight required.
Spec1.02w Graph transformations: simple transformations of f(x)1.05a Sine, cosine, tangent: definitions for all arguments1.05f Trigonometric function graphs: symmetries and periodicities

7. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{c48e6503-9d26-4f55-bdca-feadfb1afb7c-22_841_999_251_534} \captionsetup{labelformat=empty} \caption{Figure 3}
\end{figure} Figure 3 shows a plot of part of the curve \(C _ { 1 }\) with equation $$y = - 4 \cos x$$ where \(x\) is measured in radians.
Points \(P\) and \(Q\) lie on the curve and are shown in Figure 3.
  1. State
    1. the coordinates of \(P\)
    2. the coordinates of \(Q\) The curve \(C _ { 2 }\) has equation \(y = - 4 \cos x + k\) where \(x\) is measured in radians and \(k\) is a constant. Given that \(C _ { 2 }\) has a maximum \(y\) value of 11
    1. state the value of \(k\)
    2. state the coordinates of the minimum point on \(C _ { 2 }\) with the smallest positive \(x\) coordinate. On the opposite page there is a copy of Figure 3 labelled Diagram 1.
  2. Using Diagram 1, state the number of solutions of the equation $$- 4 \cos x = 5 - \frac { 10 } { \pi } x$$ giving a reason for your answer. \begin{figure}[h]
    \includegraphics[alt={},max width=\textwidth]{c48e6503-9d26-4f55-bdca-feadfb1afb7c-23_860_1016_1676_529} \captionsetup{labelformat=empty} \caption{Diagram 1}
    \end{figure}

7.

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{c48e6503-9d26-4f55-bdca-feadfb1afb7c-22_841_999_251_534}
\captionsetup{labelformat=empty}
\caption{Figure 3}
\end{center}
\end{figure}

Figure 3 shows a plot of part of the curve $C _ { 1 }$ with equation

$$y = - 4 \cos x$$

where $x$ is measured in radians.\\
Points $P$ and $Q$ lie on the curve and are shown in Figure 3.
\begin{enumerate}[label=(\alph*)]
\item State
\begin{enumerate}[label=(\roman*)]
\item the coordinates of $P$
\item the coordinates of $Q$

The curve $C _ { 2 }$ has equation $y = - 4 \cos x + k$ where $x$ is measured in radians and $k$ is a constant.

Given that $C _ { 2 }$ has a maximum $y$ value of 11
\end{enumerate}\item \begin{enumerate}[label=(\roman*)]
\item state the value of $k$
\item state the coordinates of the minimum point on $C _ { 2 }$ with the smallest positive $x$ coordinate.

On the opposite page there is a copy of Figure 3 labelled Diagram 1.
\end{enumerate}\item Using Diagram 1, state the number of solutions of the equation

$$- 4 \cos x = 5 - \frac { 10 } { \pi } x$$

giving a reason for your answer.

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{c48e6503-9d26-4f55-bdca-feadfb1afb7c-23_860_1016_1676_529}
\captionsetup{labelformat=empty}
\caption{Diagram 1}
\end{center}
\end{figure}
\end{enumerate}

\hfill \mbox{\textit{Edexcel PURE 2024 Q7}}