Question

Rewrite with only sin x and cos x.

sin 3x

Answer 1

sin(a+b)=sina⋅cosb+sinb⋅cosa

Take
sin(3x) and rewrite it to sin(x+2x)

Answer 2

2 sin x cos2x + cos x?

Answer 3

Not exactly

Answer 4

let a = x and b = 2x

Answer 5

You are close

Answer 6

2 sin x cos2x + sin3x maybe?

Answer 7

Actually I those look like possible answers.
You jumped ahead of me I was trying to tell you that using the identity I mentioned earlier you would get,
sin(x+2x)=sinx⋅cos(2x)+sin(2x)⋅cosx

Answer 8

You would use your half angle identities for cos(2x) and sin(2x) to get closer to your solution

Answer 9

What would the answer be then?