Example 4.14.  Evaluate  [Graphics:Images/ComplexGeometricSeriesMod_gr_153.gif].  

Explore Solution 4.14.

We can use the definition of convergence of a series and find the limit of the partial sums.

[Graphics:../Images/ComplexGeometricSeriesMod_gr_155.gif]




[Graphics:../Images/ComplexGeometricSeriesMod_gr_156.gif]

 

 

 

Or we can see that this is an infinite geometric series with ratio  [Graphics:../Images/ComplexGeometricSeriesMod_gr_157.gif].  

[Graphics:../Images/ComplexGeometricSeriesMod_gr_158.gif]




[Graphics:../Images/ComplexGeometricSeriesMod_gr_159.gif]

 

 

 

The sum of the infinite geometric series is now found.

[Graphics:../Images/ComplexGeometricSeriesMod_gr_160.gif]




[Graphics:../Images/ComplexGeometricSeriesMod_gr_161.gif]

 

 

 

Use Mathematica to construct some of the partial sums of the infinite series.

[Graphics:../Images/ComplexGeometricSeriesMod_gr_162.gif]




[Graphics:../Images/ComplexGeometricSeriesMod_gr_163.gif]

 

 

 

Use Mathematica to plot some of the partial sums of the infinite series.

[Graphics:../Images/ComplexGeometricSeriesMod_gr_164.gif]




[Graphics:../Images/ComplexGeometricSeriesMod_gr_165.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_166.gif]

We see that the sum of the infinite geometric series  [Graphics:../Images/ComplexGeometricSeriesMod_gr_167.gif].  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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