[tex]w=\frac{1}{z} \to \ z=\frac{1}{w}=\frac{u-iv}{u^{2} v^{2}}[/tex]
پس
[tex]y=\frac{-v}{u^{2} v^{2}}\leq 1 \Rightarrow[/tex]
[tex]u^{2} v^{2}\geq -v \Rightarrow u^{2} v^{2} v\geq 0 \Rightarrow u^{2} v^{2} v \frac{1}{4}\geq \frac{1}{4} \Rightarrow |w \frac{i}{2}|\geq \frac{1}{2}[/tex]
که گزینه ۴ میشه