The expression $\sin(A + B) - \sin(A - B)$ simplifies to:
A$2\cos A \sin B$CORRECT
B$2\sin A \cos B$
C$2\sin A \sin B$
D$2\cos A \cos B$
GCEFurther MathematicsTrigonometry and Circular Measure2024
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Why the answer is A, and why the others tempt you.
Expanding: sin(A+B) = sin A cos B + cos A sin B and sin(A−B) = sin A cos B − cos A sin B. Subtracting gives 2 cos A sin B. The sum formula sin(A+B) + sin(A−B) would give option B, a common confusion.
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