# How does sigma notation work?

##### 1 Answer

Oct 14, 2014

Sigma notation can be a bit daunting, but it's actually rather straightforward. The common way to write sigma notation is as follows:

Breaking it down into its parts:

- The
#sum# sign just means "the sum". - The
#x# at the bottom is our starting value for x. It usually has a number next to it:#sum_(x=0)# , for example, means we start at x=0 and carry on upwards until we hit... - The
#n# at the top. - The
#f(x)# is what we need to plug all these values into. At the end, we add the results obtained from here together, and that's our answer.

Note that it's not always

As an example:

means we need to find