TeX Quellcode:

\dfrac{z_1}{z_2}=\dfrac{r_1e^{i\varphi_1}}{r_2e^{i\varphi_2}}=\dfrac{r_1}{r_2}e^{i\varphi_1-i\varphi_2}=\dfrac{r_1}{r_2}e^{i(\varphi_1-\varphi_2)}