Exercise 1.  Find   [Graphics:Images/ResidueCalcModHome_gr_1.gif]   for the following functions:

1 (i).   [Graphics:Images/ResidueCalcModHome_gr_263.gif].

Solution 1 (i).

See text and/or instructor's solution manual.

Answer.   [Graphics:../Images/ResidueCalcModHome_gr_264.gif]

Solution.   Use the fact that [Graphics:../Images/ResidueCalcModHome_gr_265.gif]  and the substitution  [Graphics:../Images/ResidueCalcModHome_gr_266.gif] to express this function in the following form

                    [Graphics:../Images/ResidueCalcModHome_gr_267.gif]  

The function  [Graphics:../Images/ResidueCalcModHome_gr_268.gif]  has an essential singularity at  [Graphics:../Images/ResidueCalcModHome_gr_269.gif],  and must be expanded in a Laurent series.  

Here we have  [Graphics:../Images/ResidueCalcModHome_gr_270.gif][Graphics:../Images/ResidueCalcModHome_gr_271.gif]  and according to Definition 8.1

the residue is seen to be  [Graphics:../Images/ResidueCalcModHome_gr_272.gif].  

We are done.   

Aside.  We can let Mathematica double check our work.

[Graphics:../Images/ResidueCalcModHome_gr_273.gif]

[Graphics:../Images/ResidueCalcModHome_gr_274.gif]

Maple can check our work too!

     > series( exp(1+1/z), z=infinity,6 );

               [Graphics:../Images/ResidueCalcModHome_gr_275.gif]

We are really done.   

Aside.  [Graphics:../Images/ResidueCalcModHome_gr_276.gif] is capable of finding residues.

[Graphics:../Images/ResidueCalcModHome_gr_277.gif]

[Graphics:../Images/ResidueCalcModHome_gr_278.gif]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



This solution is complements of the authors.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(c) 2008 John H. Mathews, Russell W. Howell