Lösung 1.3:4e
Aus Online Mathematik Brückenkurs 1
(Unterschied zwischen Versionen)
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- | Because | + | Because <math>5^{9} = 5^{8+1} = 5^{8}\cdot 5^{1} = 5^{8}\cdot 5</math>, the two terms inside the brackets have <math>5^{8}</math> as a common factor and can therefore be taken outside the bracket |
- | <math>5^{9}=5^{8+1}=5^{8}\ | + | |
- | the two terms inside the brackets have | + | |
- | <math>5^{8}</math> | + | |
- | as a common factor | + | |
- | and can therefore be taken outside the bracket | + | |
+ | {{Displayed math||<math>\begin{align} | ||
+ | \bigl(5^{8}+5^{9}\bigr)^{-1} &= \bigl(5^{8}+5^{8}\cdot 5\bigr)^{-1} = \bigl(5^{8}\cdot (1+5)\bigr)^{-1}\\[5pt] | ||
+ | &= \bigl(5^{8}\cdot 6\bigr)^{-1} = 5^{8\cdot (-1)}\cdot 6^{-1} = 5^{-8}\cdot 6^{-1}. | ||
+ | \end{align}</math>}} | ||
- | + | Furthermore, <math>625 = 5\cdot 125 = 5\cdot 5\cdot 25 = 5\cdot 5\cdot 5\cdot 5 = 5^{4}</math> and we obtain | |
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- | Furthermore, | + | |
- | <math>625=5\ | + | |
- | and we obtain | + | |
- | + | ||
+ | {{Displayed math|| | ||
<math>\begin{align} | <math>\begin{align} | ||
- | + | 625\cdot \bigl(5^{8}+5^{9}\bigr)^{-1} &= 5^{4}\cdot 5^{-8}\cdot 6^{-1} = 5^{4-8}\cdot 6^{-1}\\[5pt] | |
- | + | &= 5^{-4}\cdot 6^{-1} = \frac{1}{5^{4}}\cdot \frac{1}{6}\\[5pt] | |
- | & =5^{-4}\ | + | &= \frac{1}{5^{4}\cdot 6} = \frac{1}{5\cdot 5\cdot 5\cdot 5\cdot 6}\\[5pt] |
- | + | &= \frac{1}{3750}\,\textrm{.} | |
- | & =\frac{1}{3750} \\ | + | \end{align}</math>}} |
- | \end{align}</math> | + |
Version vom 14:19, 22. Sep. 2008
Because \displaystyle 5^{9} = 5^{8+1} = 5^{8}\cdot 5^{1} = 5^{8}\cdot 5, the two terms inside the brackets have \displaystyle 5^{8} as a common factor and can therefore be taken outside the bracket
Furthermore, \displaystyle 625 = 5\cdot 125 = 5\cdot 5\cdot 25 = 5\cdot 5\cdot 5\cdot 5 = 5^{4} and we obtain