CAPE Pure Mathematics Unit 1 · 2008 (T&T) · Paper 1 · Question Q21
If 2\cos\theta + 9\sin\theta \equiv r\cos(\theta - \alpha) where r > 0 and 0 < \alpha < \frac{\pi}{2}, then the maximum value of the expression is
- (A)
\sqrt{11} - (B)
\sqrt{85} - (C)
11 - (D)
85
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