Lösung 1.3:1b
Aus Online Mathematik Brückenkurs 1
(Unterschied zwischen Versionen)
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Because <math>9=3\cdot 3=3^{2}</math>, we have | Because <math>9=3\cdot 3=3^{2}</math>, we have | ||
- | {{ | + | {{Abgesetzte Formel||<math>9^{-2}=\bigl( 3^{2} \bigr)^{-2}=3^{2\cdot (-2)}=3^{-4}</math>}} |
and thus | and thus | ||
- | {{ | + | {{Abgesetzte Formel||<math>3^{5}\cdot 9^{-2}=3^{5}\cdot 3^{-4}=3^{5-4}=3^1=3\,</math>.}} |
Version vom 08:16, 22. Okt. 2008
Before we begin to calculate, it is worthwhile looking at the expression first and investigating whether it can be simplified using the power rules, so as to reduce the arithmetical work somewhat.
Because \displaystyle 9=3\cdot 3=3^{2}, we have
\displaystyle 9^{-2}=\bigl( 3^{2} \bigr)^{-2}=3^{2\cdot (-2)}=3^{-4} |
and thus
\displaystyle 3^{5}\cdot 9^{-2}=3^{5}\cdot 3^{-4}=3^{5-4}=3^1=3\,. |