[tex]z^6=-1+i[/tex]
[tex]|-1+i|=\sqrt2[/tex]
[tex]-1+i\in cadr.II[/tex]
[tex]arg(-1+i)=\pi-\dfrac{\pi}{4}=\dfrac{3\pi}{4}[/tex]
[tex]z_k=2^{\frac{1}{12}}\left(cos\dfrac{\frac{3\pi}{4}+2k\pi}{6}+i\ sin\dfrac{\frac{3\pi}{4}+2k\pi}{6}\right);\ k\in\{0;1;2;3;4;5\}[/tex]