It's actually pretty easy, this ones just a lil tricky.
this is what i have. i wish someone cud tell me if its right lol
lim x -> 0 [tan (3x)/ xcos(x)] = ?
lim x-> 0 sin3x/xcosx = 3[lim x->0 sin3x/3x] x [lim x ->0 1/cos3x] x [lim x -> 0 1/xcosx] = 3[1] x [1] x [1/1(0)] = 0. i dunno if that last zero is right.