Kubische Gleichung/Lösung/Überprüfe/Aufgabe/Lösung

Es ist

${}{\begin{aligned}&\,\,\,\,\,\,\,{\left({\sqrt[{3}]{-1+{\sqrt {2}}}}+{\sqrt[{3}]{-1-{\sqrt {2}}}}\right)}^{3}+3{\left({\sqrt[{3}]{-1+{\sqrt {2}}}}+{\sqrt[{3}]{-1-{\sqrt {2}}}}\right)}+2\\&=-1+{\sqrt {2}}+3{\sqrt[{3}]{-1+{\sqrt {2}}}}^{2}\cdot {\sqrt[{3}]{-1-{\sqrt {2}}}}+3{\sqrt[{3}]{-1+{\sqrt {2}}}}\cdot {\sqrt[{3}]{-1-{\sqrt {2}}}}^{2}-1-{\sqrt {2}}+3{\sqrt[{3}]{-1+{\sqrt {2}}}}+3{\sqrt[{3}]{-1-{\sqrt {2}}}}+2\\&=3{\left({\sqrt[{3}]{{\left(-1+{\sqrt {2}}\right)}^{2}{\left(-1-{\sqrt {2}}\right)}}}+{\sqrt[{3}]{{\left(-1+{\sqrt {2}}\right)}{\left(-1-{\sqrt {2}}\right)}^{2}}}+{\sqrt[{3}]{-1+{\sqrt {2}}}}+{\sqrt[{3}]{-1-{\sqrt {2}}}}\right)}\\&=3{\left({\sqrt[{3}]{{\left(3-2{\sqrt {2}}\right)}{\left(-1-{\sqrt {2}}\right)}}}+{\sqrt[{3}]{{\left(-1+{\sqrt {2}}\right)}{\left(3+2{\sqrt {2}}\right)}}}+{\sqrt[{3}]{-1+{\sqrt {2}}}}+{\sqrt[{3}]{-1-{\sqrt {2}}}}\right)}\\&=3{\left({\sqrt[{3}]{1-{\sqrt {2}}}}+{\sqrt[{3}]{1+{\sqrt {2}}}}+{\sqrt[{3}]{-1+{\sqrt {2}}}}+{\sqrt[{3}]{-1-{\sqrt {2}}}}\right)}\\&=3{\left({\sqrt[{3}]{1-{\sqrt {2}}}}+{\sqrt[{3}]{1+{\sqrt {2}}}}-{\sqrt[{3}]{1-{\sqrt {2}}}}-{\sqrt[{3}]{1+{\sqrt {2}}}}\right)}\\&=0.\,\end{aligned}}$

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