Rewrite with only sin x and cos x.
-$\sin 3 x - \cos x$
A) $2 \sin ^ { 3 } x \cos ^ { 4 } x + 1$
B) $2 \sin x \cos ^ { 2 } x + \sin x - 2 \sin ^ { 3 } x - \cos x$
C) $2 \sin x - \sin ^ { 3 } x - \cos x$
D) $3 \sin x \cos x - \sin ^ { 3 } x - \cos x$

Question

Quizplus · Accepted Answer

The correct answer is obtained by using trigonometric identities to rewrite $\sin 3x$ in terms of $\sin x$ and $\cos x$. The identity for $\sin 3x$ is $\sin 3x = 3\sin x - 4\sin^3 x$. Substituting this into the original expression gives $3\sin x - 4\sin^3 x - \cos x$, which simplifies to the expression in choice B.

Rewrite with Only Sin X and Cos X sin⁡3x−cos⁡x\sin 3 x - \cos xsin3x−cosx

Rewrite with Only Sin X and Cos X $\sin 3 x - \cos x$