OCR MEI C3 — Question 6 6 marks

Exam BoardOCR MEI
ModuleC3 (Core Mathematics 3)
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicComposite & Inverse Functions
TypeFind inverse function
DifficultyStandard +0.3 This is a straightforward inverse function question requiring students to rearrange y = 1 + 2sin(3x) to make x the subject, then determine the domain from the original range. While it involves arcsin and careful attention to the restricted domain, it follows a standard procedure taught in C3 with no novel problem-solving required, making it slightly easier than average.
Spec1.02v Inverse and composite functions: graphs and conditions for existence1.05k Further identities: sec^2=1+tan^2 and cosec^2=1+cot^2

The function f(x) is defined by $$f(x) = 1 + 2\sin 3x, \quad -\frac{\pi}{6} \leqslant x \leqslant \frac{\pi}{6}.$$ You are given that this function has an inverse, \(f^{-1}(x)\). Find \(f^{-1}(x)\) and its domain. [6]

The function f(x) is defined by
$$f(x) = 1 + 2\sin 3x, \quad -\frac{\pi}{6} \leqslant x \leqslant \frac{\pi}{6}.$$

You are given that this function has an inverse, $f^{-1}(x)$.

Find $f^{-1}(x)$ and its domain. [6]

\hfill \mbox{\textit{OCR MEI C3  Q6 [6]}}