$$x\times x=\sqrt{-1}; x=?$$
$x=\sqrt{2}\left(\frac{1}{2}+\frac{1}{2}i\right)\approx 0.707106781+0.707106781i\text{, }y=\sqrt{2}\left(\frac{1}{2}+\frac{1}{2}i\right)\approx 0.707106781+0.707106781i$
$x=\sqrt{2}\left(-\frac{1}{2}-\frac{1}{2}i\right)\approx -0.707106781-0.707106781i\text{, }y=\sqrt{2}\left(-\frac{1}{2}-\frac{1}{2}i\right)\approx -0.707106781-0.707106781i$
