OCR MEI C1 2012 June — Question 11 12 marks

Exam BoardOCR MEI
ModuleC1 (Core Mathematics 1)
Year2012
SessionJune
Marks12
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicCurve Sketching
TypeHorizontal translation of factored polynomial
DifficultyModerate -0.3 This is a straightforward C1 question testing standard techniques: forming a cubic from roots, sketching using intercepts, and applying translations. All parts follow routine procedures with no problem-solving required, making it slightly easier than average, though the multi-part structure and translation work prevent it from being trivial.
Spec1.02j Manipulate polynomials: expanding, factorising, division, factor theorem1.02n Sketch curves: simple equations including polynomials1.02w Graph transformations: simple transformations of f(x)

A cubic curve has equation \(y = f(x)\). The curve crosses the \(x\)-axis where \(x = -\frac{1}{2}\), \(-2\) and \(5\).
  1. Write down three linear factors of \(f(x)\). Hence find the equation of the curve in the form \(y = 2x^3 + ax^2 + bx + c\). [4]
  2. Sketch the graph of \(y = f(x)\). [3]
  3. The curve \(y = f(x)\) is translated by \(\begin{pmatrix} 0 \\ -8 \end{pmatrix}\). State the coordinates of the point where the translated curve intersects the \(y\)-axis. [1]
  4. The curve \(y = f(x)\) is translated by \(\begin{pmatrix} 3 \\ 0 \end{pmatrix}\) to give the curve \(y = g(x)\). Find an expression in factorised form for \(g(x)\) and state the coordinates of the point where the curve \(y = g(x)\) intersects the \(y\)-axis. [4]

A cubic curve has equation $y = f(x)$. The curve crosses the $x$-axis where $x = -\frac{1}{2}$, $-2$ and $5$.

\begin{enumerate}[label=(\roman*)]
\item Write down three linear factors of $f(x)$. Hence find the equation of the curve in the form $y = 2x^3 + ax^2 + bx + c$. [4]
\item Sketch the graph of $y = f(x)$. [3]
\item The curve $y = f(x)$ is translated by $\begin{pmatrix} 0 \\ -8 \end{pmatrix}$. State the coordinates of the point where the translated curve intersects the $y$-axis. [1]
\item The curve $y = f(x)$ is translated by $\begin{pmatrix} 3 \\ 0 \end{pmatrix}$ to give the curve $y = g(x)$.

Find an expression in factorised form for $g(x)$ and state the coordinates of the point where the curve $y = g(x)$ intersects the $y$-axis. [4]
\end{enumerate}

\hfill \mbox{\textit{OCR MEI C1 2012 Q11 [12]}}