TeX Quellcode:

\begin{array}{lclcrcl}\quad\mathbb{D}&=&\mathbb{R}\setminus_{\left\{0\right\}}\cr \cr f(x) &=& \dfrac{4 x + 2}{7 x^{2}}\cr \cr \quad u(x) &=& 4 x + 2 & \Rightarrow & u'(x) &=&4\cr \quad v(x) &=&7 x^{2} & \Rightarrow & v'(x) &=& 14 x\cr \cr f'(x) &=& \dfrac{4 \cdot 7 x^{2}-\left(4 x + 2 \right)\cdot 14 x}{\left(7 x^{2}\right)^2}\cr \cr &=& \dfrac{28 x^{2}-56 x^{2}-28x}{49 x^{4}}\cr \cr &=& \dfrac{- 28 x \left(x + 1\right)}{49 x^{4}}\cr \cr &=& - \dfrac{4 x + 4}{7 x^{3}}\end{array}