cos10x sin6x-sin3x :2\1-sin5x
(sin5x + sin3x) /( cos6x sin10x - cos10x sin6x)=={2sin(5x+3x)/2 cos(5x-3x)/2} / sin(10x-6x)==(2 sin4x cos x) / sin4x) =2 cosx
cos10x sin6x-sin3x :2\1-sin5x
(sin5x + sin3x) /( cos6x sin10x - cos10x sin6x)=
={2sin(5x+3x)/2 cos(5x-3x)/2} / sin(10x-6x)=
=(2 sin4x cos x) / sin4x) =2 cosx