TeX Quellcode:
\vec{a}\cdot \vec{b} =\left(\begin{array}{c} x_1 \\ y_1 \\ z_1 \end{array}\right)\cdot \left(\begin{array}{c} x_2 \\ y_2 \\ z_2 \end{array}\right)=x_1\cdot x_2+y_1\cdot y_2+ z_1\cdot z_2