1983 AHSME Problems/Problem 11

Problem 11

Simplify $\sin (x-y) \cos y + \cos (x-y) \sin y$ .

$\textbf{(A)}\ 1\qquad \textbf{(B)}\ \sin x\qquad \textbf{(C)}\ \cos x\qquad \textbf{(D)}\ \sin x \cos 2y\qquad \textbf{(E)}\ \cos x\cos 2y$

By the addition formula for $\sin$ , this becomes $\sin{((x-y)+y)} = \sin{x}$ , so the answer is $\boxed{\textbf{(B)}}$ .

1983 AHSME (Problems • Answer Key • Resources)
Preceded by Problem 10	Followed by Problem 12
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