Question
Prove the identities.$$\sin (3 x)=3 \sin x \cos ^{2} x-\sin ^{3} x$$
Step 1
We can use the identity for $\sin(a+b)$, which is $\sin(a)\cos(b) + \cos(a)\sin(b)$. Let's take $a$ as $x$ and $b$ as $2x$. This gives us: $$\sin(3x) = \sin(x)\cos(2x) + \cos(x)\sin(2x)$$ Show more…
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