TeX Quellcode:
\begin{array} {rcl} \dfrac{1}{x+1}-\dfrac{1}{x-1} &=& \dfrac{1\cdot(x-1)}{(x+1)(x-1)}-\dfrac{1\cdot(x+1)}{(x-1)(x+1)} \cr \cr &=& \dfrac{(x-1)-(x+1)}{(x-1)(x+1)} \cr \cr &=& \dfrac{x-1-x-1}{(x-1)(x+1)} \cr \cr &=& \dfrac{- 2}{(x-1)(x+1)} \end{array}