Let S = {z: 1 < Re(z) < 2 & 1 < Im(z)}. Find the image of transformed region w-plane under bi-linear transformation of f (z) = (z + 1)/(z 1). (Hint: Note that a semi-line, a line segment or a circular arc can be transformed to a semi-line, line segment or a circular arc under bi- linear transformation. A line is specified completely, if two point on line is determined, while a circle is specified completely if three distinct points are determined.)