-1+i√3
(-------------)⁴
2
((-1+i√3)/2)^4 =((1-3-2√3i)/4)^2==((-2-2√3i)/4)^2=
=((1+√3i)/2)^2=(1-3-2√3i)/4=(-2-2√3i)/4=-(1+√3i)/2