(iv) z1z2\dfrac{z_1}{z_2}z2z1 z1z2=95(cos11π12+isin11π12)\frac{z_1}{z_2}=\frac{9}{5}\left(\cos\frac{11\pi}{12}+i\sin\frac{11\pi}{12}\right)z2z1=59(cos1211π+isin1211π) cos11π12=−6+24,sin11π12=6−24\cos\frac{11\pi}{12}=-\frac{\sqrt{6}+\sqrt{2}}{4},\quad \sin\frac{11\pi}{12}=\frac{\sqrt{6}-\sqrt{2}}{4}cos1211π=−46+2,sin1211π=46−2 z1z2=−9(6+2)20+9(6−2)20i\boxed{\frac{z_1}{z_2}=-\frac{9(\sqrt{6}+\sqrt{2})}{20}+\frac{9(\sqrt{6}-\sqrt{2})}{20}i}z2z1=−209(6+2)+209(6−2)i