Noting that E^(I Pi(1+2n))=-1 for {n,0,6}
Do[Print[Re[E^(I Pi (1 + 2 n)/7)], " ",
Im[E^(I Pi (1 + 2 n)/7)]], {n, 0, 6}]
Cos[\[Pi]/7] Sin[\[Pi]/7]
Sin[\[Pi]/14] Cos[\[Pi]/14]
-Sin[(3 \[Pi])/14] Cos[(3 \[Pi])/14]
-1 0
-Sin[(3 \[Pi])/14] -Cos[(3 \[Pi])/14]
Sin[\[Pi]/14] -Cos[\[Pi]/14]
Cos[\[Pi]/7] -Sin[\[Pi]/7]
