TeX Quellcode:

{\varphi = \arccos \left( \dfrac{ 2 \cdot \left(-1\right) + 2 \cdot 10 + 1 \cdot \left(-1\right)}{\sqrt{{2}^2+{2}^2+{1}^2} \cdot \sqrt{{\left(-1\right)}^2+{10}^2+{\left(-1\right)}^2}} \right) = \arccos \left( \dfrac{17}{\sqrt{9}\cdot\sqrt{102}} \right) \approx 55{,}87^{\circ}}