e i k . Therefore, z = cos e i k , k = , , , . Taking k = , , , , we get k = , z = cos0 i sin k = , z = cos i . Fourth roots of unity Re Im O - i - Fig.
. Fig. . Cube roots of unity Re Im O - - k = , z = cos .
k = , z = cos i . Fourth roots of unity are , , − Þ ω ω ω , where e i Note (i) In this chapter the letter ω is used for n th roots of unity. Therefore the value of ω is depending on n as shown in following table. value of n