The function `y = cos(2*(x - pi/2))`

=> `y = cos(2*x - pi)`

This function has an amplitude of 1, a period of pi and the graph is shifted by `pi/2` to the right as compared to the graph of y = cos x

`y = 2*sin(x/2 - pi/6)` has an amplitude of 2 and a period of `4*pi` . The graph is shifted to the right by `pi/3` as compared to the graph of y = sin x.