Solution 19.

See text and/or instructor's solution manual.

Solution.  Let  ,  which is analytic everywhere.  

By Cauchy's integral formulas,    and we can write

                    ,  

                    ,  

                    ,

                    

By definition we have  

                    ,

Therefore  .  

This solution is complements of the authors.

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