OCR MEI C4 2012 January — Question 3 7 marks

Exam BoardOCR MEI
ModuleC4 (Core Mathematics 4)
Year2012
SessionJanuary
Marks7
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicHarmonic Form
TypeFind value where max/min occurs
DifficultyModerate -0.3 This is a standard C4 harmonic form question requiring the R sin(x + α) transformation using R² = a² + b² and tan α = b/a, followed by finding a maximum by setting the sine term equal to 1. While it involves multiple steps, it's a routine textbook exercise with well-practiced techniques and no novel problem-solving required, making it slightly easier than average.
Spec1.05n Harmonic form: a sin(x)+b cos(x) = R sin(x+alpha) etc1.05o Trigonometric equations: solve in given intervals

Express \(3\sin x + 2\cos x\) in the form \(R\sin(x + \alpha)\), where \(R > 0\) and \(0 < \alpha < \frac{\pi}{2}\). Hence find, correct to 2 decimal places, the coordinates of the maximum point on the curve \(y = f(x)\), where $$f(x) = 3\sin x + 2\cos x, \quad 0 < x < \pi.$$ [7]

Question 3:
AnswerMarks
3B
S
A
C
T
Question 3:
3 | B
S
A
C
T
Express $3\sin x + 2\cos x$ in the form $R\sin(x + \alpha)$, where $R > 0$ and $0 < \alpha < \frac{\pi}{2}$.

Hence find, correct to 2 decimal places, the coordinates of the maximum point on the curve $y = f(x)$, where

$$f(x) = 3\sin x + 2\cos x, \quad 0 < x < \pi.$$ [7]

\hfill \mbox{\textit{OCR MEI C4 2012 Q3 [7]}}