Exercise 11.  Construct branches of  [Graphics:Images/ComplexFunLogarithmModHome_gr_1071.gif]  that are analytic at all points in the plane except at points on the following rays.  

11 (a).  [Graphics:Images/ComplexFunLogarithmModHome_gr_1072.gif].  

Solution 11 (a).

See text and/or instructor's solution manual.

Solution.   According to equation (5-20),   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1073.gif],    where   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1074.gif],  and   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1075.gif].  

Then we have   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1076.gif]   where   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1077.gif]  and  [Graphics:../Images/ComplexFunLogarithmModHome_gr_1078.gif].  

Notice that [Graphics:../Images/ComplexFunLogarithmModHome_gr_1079.gif] is not analytic on it's branch cut   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1080.gif].

We are done.   

Aside.  We can let Mathematica double check our work.

[Graphics:../Images/ComplexFunLogarithmModHome_gr_1081.gif]

[Graphics:../Images/ComplexFunLogarithmModHome_gr_1082.gif]

                    [Graphics:../Images/ComplexFunLogarithmModHome_gr_1083.gif]         [Graphics:../Images/ComplexFunLogarithmModHome_gr_1084.gif]

                    The mapping  [Graphics:../Images/ComplexFunLogarithmModHome_gr_1085.gif]   and it's branch cut   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1086.gif].

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This solution is complements of the authors.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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