Exercise 7.  Show that the following are harmonic functions in the right half-plane  [Graphics:Images/ComplexFunLogarithmModHome_gr_878.gif].  

7 (a).  [Graphics:Images/ComplexFunLogarithmModHome_gr_879.gif].  

Solution 7 (a).

See text and/or instructor's solution manual.

Answer.   [Graphics:../Images/ComplexFunLogarithmModHome_gr_880.gif],    and  [Graphics:../Images/ComplexFunLogarithmModHome_gr_881.gif]  is analytic for  [Graphics:../Images/ComplexFunLogarithmModHome_gr_882.gif].  

Solution.   

                    [Graphics:../Images/ComplexFunLogarithmModHome_gr_883.gif]    


and  [Graphics:../Images/ComplexFunLogarithmModHome_gr_884.gif]  is analytic for  [Graphics:../Images/ComplexFunLogarithmModHome_gr_885.gif].  

By Theorem 3.8 in Section 3.3 both the real and imaginary parts of an analytic function are harmonic functions.

Therefore  [Graphics:../Images/ComplexFunLogarithmModHome_gr_886.gif] is harmonic, and it follows that [Graphics:../Images/ComplexFunLogarithmModHome_gr_887.gif] is harmonic.

We are done.   

Aside.  We can let Mathematica double check our work.

[Graphics:../Images/ComplexFunLogarithmModHome_gr_888.gif]

[Graphics:../Images/ComplexFunLogarithmModHome_gr_889.gif]


[Graphics:../Images/ComplexFunLogarithmModHome_gr_890.gif]

[Graphics:../Images/ComplexFunLogarithmModHome_gr_891.gif]


[Graphics:../Images/ComplexFunLogarithmModHome_gr_892.gif]

[Graphics:../Images/ComplexFunLogarithmModHome_gr_893.gif]


[Graphics:../Images/ComplexFunLogarithmModHome_gr_894.gif]

[Graphics:../Images/ComplexFunLogarithmModHome_gr_895.gif]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



This solution is complements of the authors.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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