-1+i√3=2e^(i2π/3)
因此方程化为：(z+1)^4=2^4 e^(i8π/3)=2^4e^(i2π/3)
因此有z+1=2e^(i2π/3+i2kπ/4),k=0.1.2,3
得;z=2e^(i2π/3+ikπ/2)-1,k=0,1,2,3