Lösung 3.4:3
Aus Online Mathematik Brückenkurs 2
A polynomial equation which has real coefficients always has complex conjugate roots. We can therefore say directly that the equation, in addition to the roots \displaystyle z=\text{2}i and \displaystyle z=-\text{1}+i, has roots \displaystyle z=\overline{2i}=-2i and \displaystyle z=\overline{-\text{1}+i}=-1-i. Because the equation is of degree 4, it does not have more than 4 roots.
The answer is thus
\displaystyle \left\{ \begin{array}{*{35}l}
2i \\
-2i \\
-1+i \\
-1-i \\
\end{array} \right.
