The points z of the Argand plane for which (z - 1)/(z + i) is purely imaginary (its real part is zero, the value 0 allowed) lie on a circle, with one point of it left out. What is the radius of that circle? | StemPy Lab
The points z of the Argand plane for which z+iz−1 is purely imaginary (its real part is zero, the value 0 allowed) lie on a circle, with one point of it left out. What is the radius of that circle?