TeX Quellcode:

{\varphi = \arccos \left( \dfrac{ -17 \cdot 2 + \left(-7\right) \cdot 28 + \left(-8\right) \cdot 9}{\sqrt{{\left(-17\right)}^2+{\left(-7\right)}^2+{\left(-8\right)}^2} \cdot \sqrt{{2}^2+{28}^2+{9}^2}} \right) = \arccos \left( \dfrac{-302}{\sqrt{402}\cdot\sqrt{869}} \right) \approx 120{,}73^{\circ}}