Lösung 2.1:8c
Aus Online Mathematik Brückenkurs 1
| K  (Lösning 2.1:8c moved to Solution 2.1:8c: Robot: moved page) | |||
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| - | {{ | + | When we come across large and complicated expressions, we have to work step by step;  | 
| - | < | + | |
| - | {{ | + | as a first goal, we can multiply the top and bottom of  the fraction | 
| - | {{ | + | |
| - | < | + | |
| - | {{ | + | <math>\frac{1}{1+\frac{1}{1+x}}</math> | 
| + | |||
| + | |||
| + | by  | ||
| + | <math>1+x</math>, so as to reduce it to an expression having one fraction sign: | ||
| + | |||
| + | |||
| + | <math>\begin{align} | ||
| + | & \frac{1}{1+\frac{1}{1+\frac{1}{1+x}}}=\frac{1}{1+\frac{1}{1+\frac{1}{1+x}}\centerdot \frac{1+x}{1+x}}=\frac{1}{1+\frac{1+x}{\left( 1+\frac{1}{1+x} \right)\left( 1+x \right)}} \\  | ||
| + | &  \\  | ||
| + | & =\frac{1}{1+\frac{1+x}{1+x+\frac{1+x}{1+x}}}=\frac{1}{1+\frac{1+x}{1+x+1}}=\frac{1}{1+\frac{x+1}{x+2}} \\  | ||
| + | \end{align}</math> | ||
| + | |||
| + | |||
| + | The next step is to multiply the top and bottom of our new expression by  | ||
| + | <math>x+2</math>,  | ||
| + | so as to obtain the final answer, | ||
| + | |||
| + | |||
| + | <math>\begin{align} | ||
| + | & \frac{1}{1+\frac{x+1}{x+2}}\centerdot \frac{x+2}{x+2}=\frac{x+2}{\left( 1+\frac{x+1}{x+2} \right)\left( x+2 \right)}=\frac{x+2}{x+2+\frac{x+1}{x+2}\left( x+2 \right)} \\  | ||
| + | &  \\  | ||
| + | & \frac{x+2}{x+2+x+1}=\frac{x+2}{2x+3} \\  | ||
| + | &  \\  | ||
| + | \end{align}</math> | ||
Version vom 13:52, 16. Sep. 2008
When we come across large and complicated expressions, we have to work step by step;
as a first goal, we can multiply the top and bottom of the fraction
\displaystyle \frac{1}{1+\frac{1}{1+x}}
by 
\displaystyle 1+x, so as to reduce it to an expression having one fraction sign:
\displaystyle \begin{align}
& \frac{1}{1+\frac{1}{1+\frac{1}{1+x}}}=\frac{1}{1+\frac{1}{1+\frac{1}{1+x}}\centerdot \frac{1+x}{1+x}}=\frac{1}{1+\frac{1+x}{\left( 1+\frac{1}{1+x} \right)\left( 1+x \right)}} \\ 
&  \\ 
& =\frac{1}{1+\frac{1+x}{1+x+\frac{1+x}{1+x}}}=\frac{1}{1+\frac{1+x}{1+x+1}}=\frac{1}{1+\frac{x+1}{x+2}} \\ 
\end{align}
The next step is to multiply the top and bottom of our new expression by 
\displaystyle x+2, 
so as to obtain the final answer,
\displaystyle \begin{align}
& \frac{1}{1+\frac{x+1}{x+2}}\centerdot \frac{x+2}{x+2}=\frac{x+2}{\left( 1+\frac{x+1}{x+2} \right)\left( x+2 \right)}=\frac{x+2}{x+2+\frac{x+1}{x+2}\left( x+2 \right)} \\ 
&  \\ 
& \frac{x+2}{x+2+x+1}=\frac{x+2}{2x+3} \\ 
&  \\ 
\end{align}
 
		  