Similarly, it maps the lower half plane onto . Further, any pair of points symmetric with respect to the real axis are mapped by onto a pair of points symmetric with respect to the unit circle .
Example 3: Find the bilinear transformation which takes the points , , into the points , , .
Answer: .
Example 4: Find the most general bilinear transformation which maps the upper half plane of the -plane onto the unit open disk . Answer: where is a real constant and is a complex constant with .
Example 5: Find all Mobius transformations that map onto .
Answer: where is a real constant and is a complex constant with . |