Skip to Content

Rætur fullnægja tveimur reiknireglum sem oft eru kallaðar rótarreglurnar. Þær segja:

  • $\sqrt[n]{a \cdot b} = \sqrt[n]{a} \cdot \sqrt[n]{b}$.
  • $\displaystyle{\sqrt[n]{\frac{a}{b}} = \frac{\sqrt[n]{a}}{\sqrt[n]{b}}}$.

Dæmi:  

  • $\sqrt[4]{768} = \sqrt[4]{256 \cdot 3} = \sqrt[4]{256} \cdot \sqrt[4]{3} = 4 \cdot \sqrt[4]{3}$.

  • $\displaystyle{\sqrt[3]{\frac{27}{64}} = \frac{\sqrt[3]{27}}{\sqrt[3]{64}} = \frac3{4}}$.