TeX Quellcode:

\begin{array}{rcl}\varphi &=& \pi-\arctan\left(\dfrac{\frac{\sqrt{3}}{4}}{\frac{1}{4}}\right) \\\varphi &=& \pi-\arctan\left(\sqrt{3}\right) \\\varphi &=& \pi-\dfrac{\pi}{3} \\\varphi &=& \dfrac{2\pi}{3}\end{array}