OCR MEI C3 — Question 9 3 marks

Exam BoardOCR MEI
ModuleC3 (Core Mathematics 3)
Marks3
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicReciprocal Trig & Identities
TypeInverse trigonometric function equations
DifficultyEasy -1.2 This is a straightforward question requiring only direct evaluation of arcsin (finding x = sin(π/6) = 1/2) and then applying the standard identity arcsin x + arccos x = π/2. Both parts are routine recall with minimal calculation, making it easier than average.
Spec1.05i Inverse trig functions: arcsin, arccos, arctan domains and graphs
9 Given that \(\arcsin x = \frac { 1 } { 6 } \pi\), find \(x\). Find \(\arccos x\) in terms of \(\pi\).
Question 9:
AnswerMarks Guidance
\(x = \frac{1}{2}\)B1
\(\cos\theta = \frac{1}{2}\)M1
\(\Rightarrow \theta = \pi/3\)A1 [3] M1A0 for \(1.04\ldots\) or \(60°\) 
## Question 9:

| $x = \frac{1}{2}$ | B1 | |
|---|---|---|
| $\cos\theta = \frac{1}{2}$ | M1 | |
| $\Rightarrow \theta = \pi/3$ | A1 [3] | M1A0 for $1.04\ldots$ or $60°$ |
9 Given that $\arcsin x = \frac { 1 } { 6 } \pi$, find $x$. Find $\arccos x$ in terms of $\pi$.

\hfill \mbox{\textit{OCR MEI C3  Q9 [3]}}
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Q1 4 Q2 4 Q3 3 Q4 8 Q5 8 Q6 17 Q7 3 Q8 8 Q9 3