Express $\sin (a + b) - \sin (a - b)$ as the product of trigonometric functions.
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<|im_start|>user
Express $\sin (a + b) - \sin (a - b)$ as the product of trigonometric functions.
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user
2 \sin b \cos a
Express $\sin (a + b) - \sin (a - b)$ as the product of trigonometric functions.
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