Question

Rewrite as single trig function: sin(8x)cosx-cos(8x)sinx

I know I can simplify sin(8x) into 4sin2xcos2xcos4x, but I'm stuck after that

Answer 1

how about using

sin(a-b) = sina cosb - cosa sinb

Answer 2

using sin(a-b) =sina cosb - cosa sinb
sin (8x-1x) = sin8x cosx - cos8x sinx
therefore the answer is sin7x