Lösung 1.3:4e
Aus Online Mathematik Brückenkurs 1
(Unterschied zwischen Versionen)
			  			                                                      
		          
			K   | 
			|||
| Zeile 1: | Zeile 1: | ||
| - | 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  | |
| - | + | ||
| - | + | ||
| - | + | ||
| - | + | ||
| - | + | ||
| - | 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
