TeX Quellcode:

\dfrac{7}{5}\left(\cos\left(\dfrac{7\pi}{5}\right)+i\sin\left(\dfrac{7\pi}{5}\right)\right) \; \cdot \; \dfrac{20}{21}\left(\cos\left(\dfrac{21\pi}{20}\right)+i\sin\left(\dfrac{21\pi}{20}\right)\right)