lim x->0 cos3x - cos x /1- cos 6x

jawab

limit (x ->0) ( cos 3x - cos x )/ (1 - cos 6x)

lim(x->0)  { - 2 sin2x sin x) / (2 sin^2 3x)

x = 0 , limit =  - 2.(2x)(x) //  2(3x)(3x) = -4/18 = - 2/9