Use a sum-to-product identity to rewrite the expression.
-sin 53° - sin 25°
A) -2 sin 39° sin 14°
B) 2 cos 39° sin 14°
C) 2 cos 39° cos 14°
D) 2 sin 39° cos 14°

Name: Use a sum-to-product identity to rewrite the expression. -sin 53° - sin 25° A) -2 sin 39° sin 14° B) 2 cos 39° sin 14° C) 2 cos 39° cos 14° D) 2 sin 39° cos 14°
Brand: Quizplus
Rating: 4.8 (38 reviews)

Question

Quizplus · Accepted Answer

The sum-to-product identity for sine is sin A - sin B = 2 cos((A+B)/2) sin((A-B)/2). Applying this to sin 53° - sin 25°, we get 2 cos(39°) sin(14°).

Use a Sum-To-Product Identity to Rewrite the Expression