Summation Formulas
The linearity rule, subtotal rule, and the dominance rule are the basic properties of summations illustrated below. We also give summation formulas for
when
followed by some examples on taking limits of sums.
Proposition (Basic Rules for Sums) If
and
are real numbers that do not depend on integers
and
, then
(i) Constant Term Rule:
![]()
(ii) Sum Rule:
![]()
(iii) Scalar Multiple Rule:
![summation formulas _gr_9.gif]](pages/summation-formulas/Images/summation-formulas_gr_9.gif)
(iv) Linearity Rule:
![summation formulas _gr_10.gif]](pages/summation-formulas/Images/summation-formulas_gr_10.gif)
(v) Subtotal Rule: If
then
![summation formulas _gr_12.gif]](pages/summation-formulas/Images/summation-formulas_gr_12.gif)
(vi) Dominance Rule: If
for all
then
![]()
Proposition (Summation Formulas) The summation formulas for
when
![]()
![]()
![]()
![]()
![]()
![]()
![]()
More summations are listed below.
Example (Summation Formulas) Find the value of the sum
![summation formulas _gr_25.gif]](pages/summation-formulas/Images/summation-formulas_gr_25.gif)
Solution. We find that
![summation formulas _gr_26.gif]](pages/summation-formulas/Images/summation-formulas_gr_26.gif)
![summation formulas _gr_27.gif]](pages/summation-formulas/Images/summation-formulas_gr_27.gif)
![summation formulas _gr_28.gif]](pages/summation-formulas/Images/summation-formulas_gr_28.gif)
![]()
![]()
![]()
Example (Summation Formulas) Find the value of the sum
![summation formulas _gr_33.gif]](pages/summation-formulas/Images/summation-formulas_gr_33.gif)
Solution. We find that
![summation formulas _gr_34.gif]](pages/summation-formulas/Images/summation-formulas_gr_34.gif)
![]()
![]()
![]()
Example (Summation Formulas) Find the value of the sum
![]()
Solution. We find that
![]()
![]()
![]()
![]()
![]()
It is important to be able to evaluate limits of sums so here are a couple of examples.
Example (Summation Formulas) Evaluate the limit
![]()
Solution. We find that
![summation formulas _gr_47.gif]](pages/summation-formulas/Images/summation-formulas_gr_47.gif)
![]()
![]()
![]()
Example (Summation Formulas) Evaluate the limit
![summation formulas _gr_52.gif]](pages/summation-formulas/Images/summation-formulas_gr_52.gif)
Solution. We find that
![summation formulas _gr_53.gif]](pages/summation-formulas/Images/summation-formulas_gr_53.gif)
![summation formulas _gr_54.gif]](pages/summation-formulas/Images/summation-formulas_gr_54.gif)
![]()
![]()
![]()
Summation Formulas
Published by Library of Math -- Online math organized by subject into topics.
Written by Smith, David A.
http://www.libraryofmath.com/summation-formulas.html


