The infinite sum
can be written in a more compact way. Using the capital greek letter sigma, , we may write this sum as
We often use the following terminology when using this notation
- the general term of the sum is
- the index of summation is
- the limits of summation are 1 and , although in general the limits can be any integer, , or .
Consider the infinite series
In this example, the general term is
the index of summation is , and the limits of summation are 3 and infinity.