TeX Quellcode:
{\varphi = \arccos \left( \dfrac{ 4 \cdot \left(-1\right) + 4 \cdot \left(-9\right) + \left(-6\right) \cdot \left(-5\right)}{\sqrt{{4}^2+{4}^2+{\left(-6\right)}^2} \cdot \sqrt{{\left(-1\right)}^2+{\left(-9\right)}^2+{\left(-5\right)}^2}} \right) = \arccos \left( \dfrac{-10}{\sqrt{68}\cdot\sqrt{107}} \right) \approx 96{,}73^{\circ}}