Example 2.19.  Show that [Graphics:Images/ComplexFunLimitMod_gr_270.gif].  

Solution.  Here P and Q can be factored in the form  

            [Graphics:Images/ComplexFunLimitMod_gr_271.gif]

so that the limit is obtained by the calculation  

            [Graphics:Images/ComplexFunLimitMod_gr_272.gif]   

Explore Solution 2.19.

Enter the function f[z] and find the limit.

[Graphics:../Images/ComplexFunLimitMod_gr_273.gif]


[Graphics:../Images/ComplexFunLimitMod_gr_274.gif]

Try to evaluate f[1+i].

[Graphics:../Images/ComplexFunLimitMod_gr_275.gif]


[Graphics:../Images/ComplexFunLimitMod_gr_276.gif]

 

 

 

Let Mathematica take the limit.

[Graphics:../Images/ComplexFunLimitMod_gr_277.gif]



[Graphics:../Images/ComplexFunLimitMod_gr_278.gif]


Check out the details.
Factor the numerator and denominator of  f[z].

[Graphics:../Images/ComplexFunLimitMod_gr_279.gif]


[Graphics:../Images/ComplexFunLimitMod_gr_280.gif]

 

 

 

Find the limit of f[z] as z approaches 1 + i.

[Graphics:../Images/ComplexFunLimitMod_gr_281.gif]


[Graphics:../Images/ComplexFunLimitMod_gr_282.gif]

 

 

 

We can use Mathematica to make a mapping of a neighborhood of  [Graphics:../Images/ComplexFunLimitMod_gr_283.gif]  in the z-plane and its image in the w-plane.

[Graphics:../Images/ComplexFunLimitMod_gr_284.gif]





[Graphics:../Images/ComplexFunLimitMod_gr_285.gif]

[Graphics:../Images/ComplexFunLimitMod_gr_286.gif]

[Graphics:../Images/ComplexFunLimitMod_gr_287.gif]

[Graphics:../Images/ComplexFunLimitMod_gr_288.gif]

We see that  [Graphics:../Images/ComplexFunLimitMod_gr_289.gif].  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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