Example 2.22. Show
that the image of the right half plane
under
the mapping
is
the closed disk
in
the w-plane.
Explore Solution 2.22.
Enter the function f[z] and find its inverse.
![[Graphics:../Images/ComplexFunReciprocalMod_gr_84.gif]](../Images/ComplexFunReciprocalMod_gr_84.gif)
Solve for the inverse function and the real and imaginary parts.
![[Graphics:../Images/ComplexFunReciprocalMod_gr_86.gif]](../Images/ComplexFunReciprocalMod_gr_86.gif)
![[Graphics:../Images/ComplexFunReciprocalMod_gr_87.gif]](../Images/ComplexFunReciprocalMod_gr_87.gif)
Now find the image of the right half plane
.
![[Graphics:../Images/ComplexFunReciprocalMod_gr_90.gif]](../Images/ComplexFunReciprocalMod_gr_90.gif)
This last inequality
is
the same as
and
is the disk of radius 1 centered at w = 1 in
the w-plane.
![[Graphics:../Images/ComplexFunReciprocalMod_gr_94.gif]](../Images/ComplexFunReciprocalMod_gr_94.gif)
![[Graphics:../Images/ComplexFunReciprocalMod_gr_96.gif]](../Images/ComplexFunReciprocalMod_gr_96.gif)
![[Graphics:../Images/ComplexFunReciprocalMod_gr_97.gif]](../Images/ComplexFunReciprocalMod_gr_97.gif)
We see that the image of the right half plane
under the reciprocal transformation
is
the disk
in
the w-plane.
(c) 2006 John H. Mathews, Russell W. Howell