4.3 Geometric Series and Convergence Theorems
We begin this section by presenting a
series of the form
, 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
that
is studied in calculus. The partial sums
converge to the infinite series
on
the interval
,
and the infinite sum is
.
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_8.gif]](../Images/ComplexGeometricSeriesMod_gr_8.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_9.gif]](../Images/ComplexGeometricSeriesMod_gr_9.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_10.gif]](../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_12.gif]](../Images/ComplexGeometricSeriesMod_gr_12.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_14.gif]](../Images/ComplexGeometricSeriesMod_gr_14.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_16.gif]](../Images/ComplexGeometricSeriesMod_gr_16.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_18.gif]](../Images/ComplexGeometricSeriesMod_gr_18.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_20.gif]](../Images/ComplexGeometricSeriesMod_gr_20.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_22.gif]](../Images/ComplexGeometricSeriesMod_gr_22.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_24.gif]](../Images/ComplexGeometricSeriesMod_gr_24.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_26.gif]](../Images/ComplexGeometricSeriesMod_gr_26.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_28.gif]](../Images/ComplexGeometricSeriesMod_gr_28.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_30.gif]](../Images/ComplexGeometricSeriesMod_gr_30.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_32.gif]](../Images/ComplexGeometricSeriesMod_gr_32.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_34.gif]](../Images/ComplexGeometricSeriesMod_gr_34.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_36.gif]](../Images/ComplexGeometricSeriesMod_gr_36.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_38.gif]](../Images/ComplexGeometricSeriesMod_gr_38.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_40.gif]](../Images/ComplexGeometricSeriesMod_gr_40.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_42.gif]](../Images/ComplexGeometricSeriesMod_gr_42.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_44.gif]](../Images/ComplexGeometricSeriesMod_gr_44.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_46.gif]](../Images/ComplexGeometricSeriesMod_gr_46.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_48.gif]](../Images/ComplexGeometricSeriesMod_gr_48.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_50.gif]](../Images/ComplexGeometricSeriesMod_gr_50.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_52.gif]](../Images/ComplexGeometricSeriesMod_gr_52.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]](../Images/ComplexGeometricSeriesMod_gr_55.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_56.gif]](../Images/ComplexGeometricSeriesMod_gr_56.gif)
![[Graphics:../Images/ComplexGeometricSeriesMod_gr_57.gif]](../Images/ComplexGeometricSeriesMod_gr_57.gif)
In this module we extend geometric series to the complex numbers.