Let Riemann Sphere be $X^2 + Y^2 + (Z-1/2)^2 = \frac{1}{4}$. If $z$ is the projection of $(X,Y,Z)$ and $\frac{1}{z}$ is the projection of (X', Y', Z'), Then we can show that (X',Y',Z')=(X,-Y,1-Z).
Show that the function $\frac{1}{z}$ is represented on the Sphere by 180 degrees rotation about the diameter with endpoints $(-1/2,0,1/2)$ and $(1/2,0,1/2)$.