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 (c).  [Graphics:Images/ComplexFunLogarithmModHome_gr_1102.gif].  

Solution 11 (c).

See text and/or instructor's solution manual.

Solution.   According to equation (5-20),   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1103.gif],    where   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1104.gif],  and   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1105.gif].  

Then we have   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1106.gif]   where   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1107.gif]  and  [Graphics:../Images/ComplexFunLogarithmModHome_gr_1108.gif].  

Notice that [Graphics:../Images/ComplexFunLogarithmModHome_gr_1109.gif] is not analytic on it's branch cut   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1110.gif].

We are done.   

Aside.  We can let Mathematica double check our work.

[Graphics:../Images/ComplexFunLogarithmModHome_gr_1111.gif]

[Graphics:../Images/ComplexFunLogarithmModHome_gr_1112.gif]

                    [Graphics:../Images/ComplexFunLogarithmModHome_gr_1113.gif]          [Graphics:../Images/ComplexFunLogarithmModHome_gr_1114.gif]

               The mapping  [Graphics:../Images/ComplexFunLogarithmModHome_gr_1115.gif]   and it's branch cut   [Graphics:../Images/ComplexFunLogarithmModHome_gr_1116.gif].

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This solution is complements of the authors.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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