Express the given quantity in terms of sin x or cos x.
-$\cos ( 2 \pi - x )$
A) $\cos x + \sin x$
B) $- \cos x$
C) $\cos x - \sin x$
D) $\cos x$

Name: Express the given quantity in terms of sin x or cos x. -$\cos ( 2 \pi - x )$ A) $\cos x + \sin x$ B) $- \cos x$ C) $\cos x - \sin x$ D) $\cos x$
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Question

Quizplus · Accepted Answer

Using the formula for cosine of difference of angles, we have:
$$\cos(2\pi-x) = \cos 2\pi \cos x + \sin 2\pi \sin x = \cos x$$
since $\cos 2\pi = 1$ and $\sin 2\pi = 0$. Therefore, the answer is D.

Express the Given Quantity in Terms of Sin X or Cos