Lösung 3.1:3d
Aus Online Mathematik Brückenkurs 1
(Unterschied zwischen Versionen)
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- | {{ | + | We can multiply |
- | < | + | <math>\sqrt{\frac{2}{3}}</math> |
- | {{ | + | into the bracket and then write the root expressions together under a common root sign using the rule |
+ | <math>\sqrt{a}\centerdot \sqrt{b}=\sqrt{ab}</math> | ||
+ | |||
+ | |||
+ | |||
+ | <math>\sqrt{\frac{2}{3}}\left( \sqrt{6}-\sqrt{3} \right)=\sqrt{\frac{2}{3}}\centerdot \sqrt{6}-\sqrt{\frac{2}{3}}\centerdot \sqrt{3}=\sqrt{\frac{2\centerdot 6}{3}}-\sqrt{\frac{2\centerdot 3}{3}}.</math> | ||
+ | |||
+ | Because | ||
+ | <math>\frac{2\centerdot 6}{3}=2\centerdot 2=2^{2}</math> | ||
+ | and | ||
+ | <math>\frac{2\centerdot 3}{3}=2</math>, we obtain | ||
+ | |||
+ | |||
+ | <math>\sqrt{\frac{2}{3}}\left( \sqrt{6}-\sqrt{3} \right)=\sqrt{2^{2}}-\sqrt{2}=2-\sqrt{2}</math> |
Version vom 13:07, 22. Sep. 2008
We can multiply \displaystyle \sqrt{\frac{2}{3}} into the bracket and then write the root expressions together under a common root sign using the rule \displaystyle \sqrt{a}\centerdot \sqrt{b}=\sqrt{ab}
\displaystyle \sqrt{\frac{2}{3}}\left( \sqrt{6}-\sqrt{3} \right)=\sqrt{\frac{2}{3}}\centerdot \sqrt{6}-\sqrt{\frac{2}{3}}\centerdot \sqrt{3}=\sqrt{\frac{2\centerdot 6}{3}}-\sqrt{\frac{2\centerdot 3}{3}}.
Because \displaystyle \frac{2\centerdot 6}{3}=2\centerdot 2=2^{2} and \displaystyle \frac{2\centerdot 3}{3}=2, we obtain
\displaystyle \sqrt{\frac{2}{3}}\left( \sqrt{6}-\sqrt{3} \right)=\sqrt{2^{2}}-\sqrt{2}=2-\sqrt{2}