OCR MEI C1 2013 June — Question 12 12 marks

Exam BoardOCR MEI
ModuleC1 (Core Mathematics 1)
Year2013
SessionJune
Marks12
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicFactor & Remainder Theorem
TypeShow equation reduces to polynomial
DifficultyStandard +0.3 This is a structured multi-part question requiring graphical work, algebraic manipulation to form a quadratic, solving using the quadratic formula, and applying the discriminant condition for tangency. While it involves several techniques, each step is clearly signposted and follows standard C1 procedures without requiring novel insight or complex problem-solving.
Spec1.02d Quadratic functions: graphs and discriminant conditions1.02f Solve quadratic equations: including in a function of unknown1.02o Sketch reciprocal curves: y=a/x and y=a/x^21.02q Use intersection points: of graphs to solve equations

\includegraphics{figure_12} Fig. 12 shows the graph of \(y = \frac{1}{x - 2}\).
  1. Draw accurately the graph of \(y = 2x + 3\) on the copy of Fig. 12 and use it to estimate the coordinates of the points of intersection of \(y = \frac{1}{x - 2}\) and \(y = 2x + 3\). [3]
  2. Show algebraically that the \(x\)-coordinates of the points of intersection of \(y = \frac{1}{x - 2}\) and \(y = 2x + 3\) satisfy the equation \(2x^2 - x - 7 = 0\). Hence find the exact values of the \(x\)-coordinates of the points of intersection. [5]
  3. Find the quadratic equation satisfied by the \(x\)-coordinates of the points of intersection of \(y = \frac{1}{x - 2}\) and \(y = -x + k\). Hence find the exact values of \(k\) for which \(y = -x + k\) is a tangent to \(y = \frac{1}{x - 2}\). [4]

\includegraphics{figure_12}

Fig. 12 shows the graph of $y = \frac{1}{x - 2}$.
\begin{enumerate}[label=(\roman*)]
\item Draw accurately the graph of $y = 2x + 3$ on the copy of Fig. 12 and use it to estimate the coordinates of the points of intersection of $y = \frac{1}{x - 2}$ and $y = 2x + 3$. [3]
\item Show algebraically that the $x$-coordinates of the points of intersection of $y = \frac{1}{x - 2}$ and $y = 2x + 3$ satisfy the equation $2x^2 - x - 7 = 0$. Hence find the exact values of the $x$-coordinates of the points of intersection. [5]
\item Find the quadratic equation satisfied by the $x$-coordinates of the points of intersection of $y = \frac{1}{x - 2}$ and $y = -x + k$. Hence find the exact values of $k$ for which $y = -x + k$ is a tangent to $y = \frac{1}{x - 2}$. [4]
\end{enumerate}

\hfill \mbox{\textit{OCR MEI C1 2013 Q12 [12]}}