OCR MEI C3 2011 January — Question 7 8 marks

Exam BoardOCR MEI
ModuleC3 (Core Mathematics 3)
Year2011
SessionJanuary
Marks8
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicComposite & Inverse Functions
TypeFind inverse function
DifficultyStandard +0.3 This question tests standard C3 content on inverse trigonometric functions and their inverses. Part (i) requires knowing the range of arctan (which is -π/2 to π/2) and applying a simple transformation. Part (ii) involves routine algebraic manipulation to find the inverse function and sketching by reflection in y=x. While it requires understanding of arctan properties, the techniques are straightforward and commonly practiced, making it slightly easier than average.
Spec1.02v Inverse and composite functions: graphs and conditions for existence1.05i Inverse trig functions: arcsin, arccos, arctan domains and graphs

Fig. 7 shows the curve \(y = f(x)\), where \(f(x) = 1 + 2 \arctan x\), \(x \in \mathbb{R}\). The scales on the \(x\)- and \(y\)-axes are the same. \includegraphics{figure_7}
  1. Find the range of f, giving your answer in terms of \(\pi\). [3]
  2. Find \(f^{-1}(x)\), and add a sketch of the curve \(y = f^{-1}(x)\) to the copy of Fig. 7. [5]

Fig. 7 shows the curve $y = f(x)$, where $f(x) = 1 + 2 \arctan x$, $x \in \mathbb{R}$. The scales on the $x$- and $y$-axes are the same.

\includegraphics{figure_7}

\begin{enumerate}[label=(\roman*)]
\item Find the range of f, giving your answer in terms of $\pi$.
[3]

\item Find $f^{-1}(x)$, and add a sketch of the curve $y = f^{-1}(x)$ to the copy of Fig. 7.
[5]
\end{enumerate}

\hfill \mbox{\textit{OCR MEI C3 2011 Q7 [8]}}