OCR MEI C1 2009 June — Question 12 13 marks

Exam BoardOCR MEI
ModuleC1 (Core Mathematics 1)
Year2009
SessionJune
Marks13
PaperDownload PDF ↗
TopicCurve Sketching
TypeHorizontal translation of factored polynomial
DifficultyModerate -0.8 This is a straightforward C1 question testing routine algebraic expansion, basic curve sketching from factored form, simple transformations, and factor theorem with quadratic formula. All parts follow standard textbook procedures with no problem-solving insight required, making it easier than average.
Spec1.02f Solve quadratic equations: including in a function of unknown1.02j Manipulate polynomials: expanding, factorising, division, factor theorem1.02n Sketch curves: simple equations including polynomials1.02w Graph transformations: simple transformations of f(x)

  1. You are given that \(\text{f}(x) = (x + 1)(x - 2)(x - 4)\).
    1. Show that \(\text{f}(x) = x^3 - 5x^2 + 2x + 8\). [2]
    2. Sketch the graph of \(y = \text{f}(x)\). [3]
    3. The graph of \(y = \text{f}(x)\) is translated by \(\begin{pmatrix} 3 \\ 0 \end{pmatrix}\). State an equation for the resulting graph. You need not simplify your answer. Find the coordinates of the point at which the resulting graph crosses the \(y\)-axis. [3]
  2. Show that 3 is a root of \(x^3 - 5x^2 + 2x + 8 = -4\). Hence solve this equation completely, giving the other roots in surd form. [5]

\begin{enumerate}[label=(\roman*)]
\item You are given that $\text{f}(x) = (x + 1)(x - 2)(x - 4)$.
\begin{enumerate}[label=(\alph*)]
\item Show that $\text{f}(x) = x^3 - 5x^2 + 2x + 8$. [2]
\item Sketch the graph of $y = \text{f}(x)$. [3]
\item The graph of $y = \text{f}(x)$ is translated by $\begin{pmatrix} 3 \\ 0 \end{pmatrix}$.

State an equation for the resulting graph. You need not simplify your answer.

Find the coordinates of the point at which the resulting graph crosses the $y$-axis. [3]
\end{enumerate}
\item Show that 3 is a root of $x^3 - 5x^2 + 2x + 8 = -4$. Hence solve this equation completely, giving the other roots in surd form. [5]
\end{enumerate}

\hfill \mbox{\textit{OCR MEI C1 2009 Q12 [13]}}