Summation Notation

9.1: Sequences and Series- Summation Notation

Sequence:
3,7,11,15,....

Series: A series is the sum of a sequence.
3+7+11+15...

                                          (Upper Limit)

                                          (Lower Limit)

This greek letter is known as Sigma.  It represents the sum of something.  In this case it represents the sum of a series.  Sigma with an upper limit, lower limit, and explicit formula is called summation notation.


Example:

                                                            10

                                                            n=1

This is the partial sum starting with the lower limit of n=1, ending with the last term being 10 (upper limit), and using the explicit formula. 

The sum of this series = 160 when you add all of the terms of the partial sum together. 

To solve this on a calculator:

sum(seq(explicit formula (2n+5), variable (x), lower limit (1), upper limit (10))

This is a faster way to find the sum instead of adding each term up individualy.