I believe he means solve z^3=1. Yo
u will get 3 roots one of these roots will be 1, the other will be cis(n/3) and the other will be cis(2n/3).
let w= cis(n/3)
consider: cis(2n/3)=[cis(n/3)}^2, by demoivre's thereom
therefore, cis(2n/3)=w^2
thus, w^2 is also a cube root of unity
note: n...