Exercise 5.  Evaluate  [Graphics:Images/ContourIntegralModHome_gr_208.gif]  from  [Graphics:Images/ContourIntegralModHome_gr_209.gif]  along the following contours, as shown in Figures 6.13 (a)  and  6.13 (b).  

5 (b).  The contour C that is the upper half of the circle  [Graphics:Images/ContourIntegralModHome_gr_264.gif],   oriented clockwise,   as shown in Figures 6.13 (b).

                    [Graphics:Images/ContourIntegralModHome_gr_265.gif]

                                   Figure 6.13 (a).  The contour  [Graphics:Images/ContourIntegralModHome_gr_266.gif].  

Solution 5 (b).

See text and/or instructor's solution manual.

Answer.  [Graphics:../Images/ContourIntegralModHome_gr_267.gif].  

                              [Graphics:../Images/ContourIntegralModHome_gr_268.gif]

                    Figure 6.13 (b).  The contour   [Graphics:../Images/ContourIntegralModHome_gr_269.gif]   for   [Graphics:../Images/ContourIntegralModHome_gr_270.gif].

Solution Method I.  The function is   [Graphics:../Images/ContourIntegralModHome_gr_271.gif]   and the curve is   [Graphics:../Images/ContourIntegralModHome_gr_272.gif]   and we obtain

                    [Graphics:../Images/ContourIntegralModHome_gr_273.gif]   and   [Graphics:../Images/ContourIntegralModHome_gr_274.gif],   
                    
                    then

                     [Graphics:../Images/ContourIntegralModHome_gr_275.gif]  

The last two real integrals are computed using

                    [Graphics:../Images/ContourIntegralModHome_gr_276.gif]  

                    and

                    [Graphics:../Images/ContourIntegralModHome_gr_277.gif]  

We are done.  

Solution Method II.  We could use a method that uses the following complex computations.

                         [Graphics:../Images/ContourIntegralModHome_gr_278.gif]

                    Figure 6.13 (b).  The contour   [Graphics:../Images/ContourIntegralModHome_gr_279.gif]   for   [Graphics:../Images/ContourIntegralModHome_gr_280.gif].

The function is   [Graphics:../Images/ContourIntegralModHome_gr_281.gif]   and the curve is  [Graphics:../Images/ContourIntegralModHome_gr_282.gif]  for  [Graphics:../Images/ContourIntegralModHome_gr_283.gif]  and

from Section 1.2 we apply the formula   [Graphics:../Images/ContourIntegralModHome_gr_284.gif].   Then we obtain

                    [Graphics:../Images/ContourIntegralModHome_gr_285.gif]   and   [Graphics:../Images/ContourIntegralModHome_gr_286.gif],  
                    
                    then

                     [Graphics:../Images/ContourIntegralModHome_gr_287.gif]  

Here we have used the calculations indicated by equation (6-8) in Section 6.1:

                    [Graphics:../Images/ContourIntegralModHome_gr_288.gif]   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This solution is complements of the authors.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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