Quadratic Equation/Examples/z^6 + z^3 + 1 = 0

Example of Quadratic Equation
The sextic equation:
 * $z^6 + z^3 + 1 = 0$

has the solutions:


 * $z = \begin{cases} \cos \dfrac {2 \pi} 9 \pm i \sin \dfrac {2 \pi} 9 \\ \cos \dfrac {4 \pi} 9 \pm i \sin \dfrac {4 \pi} 9 \\ \cos \dfrac {8 \pi} 9 \pm i \sin \dfrac {8 \pi} 9 \end{cases}$