Question

Rewrite with only sin x and cos x.

sin 3x - cos x

Answer 1

These are the choices.

Answer 2

sin3x = sin(x+2x) = sinxcos2x + cosx sin2x

sinx (cos^2x- sin^2x) + cosx * 2 sinx cosx

sinxcos^2x - sin^3x + 2sinxcos^2x


3sinxcos^2x - sin^3x - cosx

Answer 3

so it's B

Answer 4

Oh I see, I was getting confused because the answers looked different but now I realize they are the same.

Answer 5

2sinxcos^2x + sinx(1-2sin^2x) - cosx

2sinxcos^2x + sinx cos2x - cosx


2sinxcos^2x + (cos^2x - sin^2x) sinx - cosx

2sinxcos^2x + sinxcos^2x - sin^3x - cosx

3sinxcos^2x - sin^3x - cosx

Answer 6

Thank you!