TeX Quellcode:
\begin{array}{rclcl} \sin(\alpha) &=& \dfrac{a}{c} &\vert& \cdot c \cr a &=& c\cdot \sin(\alpha) \cr \cr \cos(\alpha) &=& \dfrac{b}{c} &\vert& \cdot c \cr b &=& c\cdot \cos(\alpha) \end{array}