設複數平面上的相異四點 z_1,z_2,z_3,z_4 依序且依逆時針方向可連成一個正方形。下列哪一個選項為 \frac{z_2-z_1}{z_3-z_1} 之值？
z_1,z_2,z_3,z_4
\frac{z_2-z_1}{z_3-z_1}
\sqrt{2}\cos(\frac{\pi}{4})+\sqrt{2}\,i\sin(\frac{\pi}{4})
\sqrt{2}\cos(-\frac{\pi}{4})+\sqrt{2}\,i\sin(-\frac{\pi}{4})
\frac{1}{\sqrt{2}}\cos(\frac{\pi}{4})+\frac{1}{\sqrt{2}}\,i\sin(\frac{\pi}{4})
\frac{1}{\sqrt{2}}\cos(-\frac{\pi}{4})+\frac{1}{\sqrt{2}}\,i\sin(-\frac{\pi}{4})
\cos(\frac{\pi}{4})+i\sin(\frac{\pi}{4})
