Extra Example 1.  Show that  [Graphics:Images/HarmonicFunctionMod._gr_160.gif]  is a harmonic function and find the harmonic conjugate  [Graphics:Images/HarmonicFunctionMod._gr_161.gif].

Explore Extra Solution 1.

Enter the function u[x,y], do a step by step construction.

[Graphics:../Images/HarmonicFunctionMod._gr_162.gif]




[Graphics:../Images/HarmonicFunctionMod._gr_163.gif]

[Graphics:../Images/HarmonicFunctionMod._gr_164.gif]

 

 

 

We are done!

Aside.  We can also construct v[x,y] by the following alternative method.

Enter the function u[x,y], and determine if it is a harmonic function.  If so, proceed with the construction of the harmonic conjugate v[x,y].

[Graphics:../Images/HarmonicFunctionMod._gr_165.gif]




[Graphics:../Images/HarmonicFunctionMod._gr_166.gif]

 

 

 

Form the analytic function  f[z] = u[x,y]+ i v[x,y]  and verify that the Cauchy-Riemann equations hold.

[Graphics:../Images/HarmonicFunctionMod._gr_167.gif]




[Graphics:../Images/HarmonicFunctionMod._gr_168.gif]

 

 

Therefore  [Graphics:../Images/HarmonicFunctionMod._gr_169.gif] is the harmonic conjugate of  [Graphics:../Images/HarmonicFunctionMod._gr_170.gif].  

Aside.
  We can use Mathematica to get the standard form of an analytic function.  

[Graphics:../Images/HarmonicFunctionMod._gr_171.gif]




[Graphics:../Images/HarmonicFunctionMod._gr_172.gif]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(c) 2006 John H. Mathews, Russell W. Howell