4.3  Geometric Series and Convergence Theorems

    We begin this section by presenting a series of the form   [Graphics:Images/ComplexGeometricSeriesMod_gr_1.gif],  which is called a geometric series and is one of the most important series in mathematics.

Real Exploration.

    The complex geometric series is a generalization of the real geometric series  [Graphics:../Images/ComplexGeometricSeriesMod_gr_2.gif]  that is studied in calculus.  The partial sums [Graphics:../Images/ComplexGeometricSeriesMod_gr_3.gif] converge to the infinite series  [Graphics:../Images/ComplexGeometricSeriesMod_gr_4.gif]  on the interval [Graphics:../Images/ComplexGeometricSeriesMod_gr_5.gif], and the infinite sum is  [Graphics:../Images/ComplexGeometricSeriesMod_gr_6.gif].

[Graphics:../Images/ComplexGeometricSeriesMod_gr_7.gif]




[Graphics:../Images/ComplexGeometricSeriesMod_gr_8.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_9.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_10.gif]

 

 

 

We can use Mathematica to draw a series of graph which illustrate the convergence of the partial sums to the infinite sum.

[Graphics:../Images/ComplexGeometricSeriesMod_gr_11.gif]





[Graphics:../Images/ComplexGeometricSeriesMod_gr_12.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_13.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_14.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_15.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_16.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_17.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_18.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_19.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_20.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_21.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_22.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_23.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_24.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_25.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_26.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_27.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_28.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_29.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_30.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_31.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_32.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_33.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_34.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_35.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_36.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_37.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_38.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_39.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_40.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_41.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_42.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_43.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_44.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_45.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_46.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_47.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_48.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_49.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_50.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_51.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_52.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_53.gif]


The following might give an insight into what happens when a complex number is used instead of a real number.





[Graphics:../Images/ComplexGeometricSeriesMod_gr_55.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_56.gif]

[Graphics:../Images/ComplexGeometricSeriesMod_gr_57.gif]

In this module we extend geometric series to the complex numbers.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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