Write the product as a sum or difference of trigonometric functions.
-$2 \sin 4 x \sin 14 x$
A) $\frac { 1 } { 2 } ( \cos 18 x + \cos 10 x )$
B) $\cos 10 x - \cos 18 x$
C) $\sin 18 x + \sin 10 x$
D) $\cos 18 x + \cos 10 x$

Question

Quizplus · Accepted Answer

Using the product-to-sum identities, $2 \sin A \sin B = \cos(A-B) - \cos(A+B)$, we have $2 \sin 4x \sin 14x = \cos(10x) - \cos(18x)$.

Write the Product as a Sum or Difference of Trigonometric 2sin⁡4xsin⁡14x2 \sin 4 x \sin 14 x2sin4xsin14x

Write the Product as a Sum or Difference of Trigonometric $2 \sin 4 x \sin 14 x$