let x=(1+z0)(1+z02)............(1+z02n)
(1-z0)x=(1-z02)(1+z02)...................1+z02n)
(1-z0)x = (1-z02n+1)
x=(1-z02n+1)/(1-z0)
now u can do by putting z0=1+i/2
let x=(1+z0)(1+z02)............(1+z02n)
(1-z0)x=(1-z02)(1+z02)...................1+z02n)
(1-z0)x = (1-z02n+1)
x=(1-z02n+1)/(1-z0)
now u can do by putting z0=1+i/2