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

1 (g).   [Graphics:Images/ResidueCalcModHome_gr_222.gif].

Solution 1 (g).

See text and/or instructor's solution manual.

Answer.   [Graphics:../Images/ResidueCalcModHome_gr_223.gif]

Solution.   Use the fact that  [Graphics:../Images/ResidueCalcModHome_gr_224.gif]  and express this function in the following form

                    [Graphics:../Images/ResidueCalcModHome_gr_225.gif]  

The function  [Graphics:../Images/ResidueCalcModHome_gr_226.gif]  has a removable singularity at [Graphics:../Images/ResidueCalcModHome_gr_227.gif].  

Here we have  [Graphics:../Images/ResidueCalcModHome_gr_228.gif][Graphics:../Images/ResidueCalcModHome_gr_229.gif]  and according to Definition 8.1  

the residue is seen to be  [Graphics:../Images/ResidueCalcModHome_gr_230.gif].  

We are done.   

Aside.  We can let Mathematica double check our work.

[Graphics:../Images/ResidueCalcModHome_gr_231.gif]

[Graphics:../Images/ResidueCalcModHome_gr_232.gif]

Maple can check our work too!

     > series( sin(z)/z, z=0,12 );

               [Graphics:../Images/ResidueCalcModHome_gr_233.gif]

We are really really done.   

Aside.  Both [Graphics:../Images/ResidueCalcModHome_gr_234.gif] and [Graphics:../Images/ResidueCalcModHome_gr_235.gif] are capable of finding residues.

[Graphics:../Images/ResidueCalcModHome_gr_236.gif]

[Graphics:../Images/ResidueCalcModHome_gr_237.gif]


     > residue( sin(z)/z, z=0 );

               0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This solution is complements of the authors.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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