cos6xcos3x=sin6xsin3x
cos3x=tg6xsin3x
tg6x=ctg6x
sin6x/cos6x=cos6x/sin6x
cos^2 6x-sin^2 6x=0
cos12x=0
12x=p/2+pk
x=p/24+pk/12; k принадлежит Z
cos6xcos3x=sin6xsin3x
cos3x=tg6xsin3x
tg6x=ctg6x
sin6x/cos6x=cos6x/sin6x
cos^2 6x-sin^2 6x=0
cos12x=0
12x=p/2+pk
x=p/24+pk/12; k принадлежит Z