Sigma notation  Sequences and Series
Sigma notation
Don’t you find it tiring when we express a series with many terms using numerous addition and/or subtraction signs? Don’t you wish that we have something to symbolise this action? Well we have a solution, introducing the “Sigma Notation”! In this section, we will learn how to utilise the sigma notation to represent a series, as well as how to evaluate it.
Related concepts:
 Introduction to sequences
 Introduction to infinite series
Lessons
Notes:
$\sum_{i=1}^n$(an equation containing $i$)
$\sum$ : "Sigma"; summation of $i^{th}$ term to $n^{th}$ term
$i$ : index, a counter for the $i^{th}$ term
$n$ : index of ending term

1.
Evaluate the following arithmetic series:

3.
Evaluate the following geometric series:

6.
Evaluate the following infinite geometric series:

7.
Write the following sum in sigma notation, then evaluate