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Question
Given A = 60° and B = 30°,
prove that : sin (A + B) = sin A cos B + cos A sin B
Solution
Given A = 60° and B = 30°
LHS = sin(A + B)
= sin (60° + 30°)
= sin 90°
= 1
RHS = sin A cos B + cos A sin B
= sin 60° cos 30° + cos 60° sin 30°
= `(sqrt3)/(2) (sqrt3)/(2) + (1)/(2) (1)/(2)`
= `(3)/(4) + (1)/(4)`
= 1
LHS = RHS
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