Example 2.12.  Show that the transformation  [Graphics:Images/ComplexFunPowerRoot_gr_30.gif],  usually maps vertical and horizontal lines onto parabolas and use this fact to find the image of the rectangle [Graphics:Images/ComplexFunPowerRoot_gr_31.gif].  (a) Find the image of the vertical line  [Graphics:Images/ComplexFunPowerRoot_gr_32.gif].  (b) Find the image of the horizontal line  [Graphics:Images/ComplexFunPowerRoot_gr_33.gif].  

Explore Solution 2.12.

Enter the function w = f[z] and determine the real and imaginary parts.

[Graphics:../Images/ComplexFunPowerRoot_gr_69.gif]



[Graphics:../Images/ComplexFunPowerRoot_gr_70.gif]

 

 

(a) Find the image of the vertical line  [Graphics:../Images/ComplexFunPowerRoot_gr_71.gif].  

[Graphics:../Images/ComplexFunPowerRoot_gr_72.gif]



[Graphics:../Images/ComplexFunPowerRoot_gr_73.gif]

Hence, the image of the vertical line  [Graphics:../Images/ComplexFunPowerRoot_gr_74.gif]  is the parabola  [Graphics:../Images/ComplexFunPowerRoot_gr_75.gif].  

 

(b) Find the image of the horizontal line  [Graphics:../Images/ComplexFunPowerRoot_gr_76.gif].  

[Graphics:../Images/ComplexFunPowerRoot_gr_77.gif]



[Graphics:../Images/ComplexFunPowerRoot_gr_78.gif]

Hence, the image of the horizontal line  [Graphics:../Images/ComplexFunPowerRoot_gr_79.gif]  is the parabola  [Graphics:../Images/ComplexFunPowerRoot_gr_80.gif].  

 

Use Mathematica to make a graph of the mapping.

[Graphics:../Images/ComplexFunPowerRoot_gr_81.gif]



[Graphics:../Images/ComplexFunPowerRoot_gr_82.gif]

[Graphics:../Images/ComplexFunPowerRoot_gr_83.gif]

[Graphics:../Images/ComplexFunPowerRoot_gr_84.gif]

[Graphics:../Images/ComplexFunPowerRoot_gr_85.gif]

 

 

 

 

[Graphics:../Images/ComplexFunPowerRoot_gr_86.gif]



[Graphics:../Images/ComplexFunPowerRoot_gr_87.gif]

[Graphics:../Images/ComplexFunPowerRoot_gr_88.gif]

[Graphics:../Images/ComplexFunPowerRoot_gr_89.gif]

[Graphics:../Images/ComplexFunPowerRoot_gr_90.gif]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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