-2+2i=2√2*(cos(π3/4)+i*sin(3π/4))=2√2*e^(3*π*i/4)
(-2+2i)^(1/3)=('2√2)^(1/3)*e^((3*π*i/4)/3)=√2*e^(π*i/4)=√2*(cos(π/4)+i*sin(π/4))=1+i