write the expression as the sine or cosine of an angle.

sin 3x cos x - cos 3x sin x

In other words, you'll type "sin" without quotes in the green box.

Also, you'll type "2" in the gray box, which also won't have quotes.

Explanation:

We'll use the first hint. Note the pattern of sin cos +-  cos sin which matches (somewhat) with the original expression.

Specifically, we'll use this identity

sin(A - B) = sin(A)cos(B) - cos(A)sin(B)

In this case, A = 3x and B = x

So,

sin(A - B) = sin(A)cos(B) - cos(A)sin(B)

sin(A)cos(B) - cos(A)sin(B) = sin(A - B)

sin(3x)cos(x) - cos(3x)sin(x) = sin(3x - x)

sin(3x)cos(x) - cos(3x)sin(x) = sin(2x)

answer: huh

step-by-step explanation: