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Question
Express the following as the sum or difference of sine or cosine:
cos 7θ sin 3θ
Sum
Solution
= `1/2` [sin(7θ + 3θ) – sin(7θ – 3θ)]
= `1/2` (sin 10θ – sin 4θ)
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Transformation Formulae
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Chapter 4: Trigonometry - Exercise 4.3 [Page 88]
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