1.y =1/2cos2 (x-π/6) is to shift cosx to the right by π/6 and then reduce the abscissa and ordinate by 2 times respectively.

2.y=3sin 1/2(x+π/3) is to shift sinx to the left by π/3, then expand the abscissa by 2 times and the ordinate by 3 times.

Five-point drawing should take the point where y=0 and the point where y is the largest and smallest.