2010013101

Nech $z_1=4(\cos \frac{7\pi }{3}+\mathrm{i}\sin \frac{7\pi }{3})$ a $z_2=\frac{1}{2}(\cos \frac{\pi }{6}+\mathrm{i}\sin \frac{\pi }{6})$, vypočítajte $z_1\cdot z_2$.