Example 10.5.  Find the bilinear transformation  w = S(z)  that maps the points  [Graphics:Images/MobiusTranformationMod_gr_123.gif]  onto the points  [Graphics:Images/MobiusTranformationMod_gr_124.gif],  respectively.

[Graphics:Images/MobiusTranformationMod_gr_125.gif]

Explore Solution 10.5.

Enter the three points and their images and solve for  w = S(z).  

[Graphics:../Images/MobiusTranformationMod_gr_133.gif]




[Graphics:../Images/MobiusTranformationMod_gr_134.gif]

 

 

 

 

This is equivalent to the formula  [Graphics:../Images/MobiusTranformationMod_gr_135.gif],  and can be verified by a computation.

[Graphics:../Images/MobiusTranformationMod_gr_136.gif]



[Graphics:../Images/MobiusTranformationMod_gr_137.gif]

 

 

 

Check our work and look at the images of  [Graphics:../Images/MobiusTranformationMod_gr_138.gif].  

[Graphics:../Images/MobiusTranformationMod_gr_139.gif]



[Graphics:../Images/MobiusTranformationMod_gr_140.gif]

 

 

 

To visualize the mapping  w = S(z)  we will consider a graph.

[Graphics:../Images/MobiusTranformationMod_gr_141.gif]





[Graphics:../Images/MobiusTranformationMod_gr_142.gif]

[Graphics:../Images/MobiusTranformationMod_gr_143.gif]

[Graphics:../Images/MobiusTranformationMod_gr_144.gif]

[Graphics:../Images/MobiusTranformationMod_gr_145.gif]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(c) 2006 John H. Mathews, Russell W. Howell