Rewrite the following as a product of trigonometric functions.
-$\cos ( - x ) \cos x - \sin ( - x ) \sin x$
A) 1
B) 2
C) $\cos ^ { 2 } x \sin ^ { 2 } x$
D) 0

Question

Quizplus · Accepted Answer

This expression can be simplified using the trigonometric identity for the cosine of a difference, which states that $\cos(A - B) = \cos A \cos B + \sin A \sin B$. Applying this identity with $A = x$ and $B = x$, and considering that $\cos(-x) = \cos(x)$ and $\sin(-x) = -\sin(x)$, the expression simplifies to $\cos(0)$, which equals 1.

Rewrite the Following as a Product of Trigonometric Functions cos⁡(−x)cos⁡x−sin⁡(−x)sin⁡x\cos ( - x ) \cos x - \sin ( - x ) \sin xcos(−x)cosx−sin(−x)sinx

Rewrite the Following as a Product of Trigonometric Functions $\cos ( - x ) \cos x - \sin ( - x ) \sin x$