# What is sigma?

1. May 1, 2004

### lvlastermind

I would like to know what sigma is and what it does.

What is sigma?
What does it stand for?
How does it work?
Do you have any examples of how it works?

any help would be appreciated

(im not sure if this should be in the calc section or not)

2. May 1, 2004

### philosophking

Sigma is a greek letter that looks like an E.

Sigma is a sign usually indicating summation.

It works by having some expression to the right of it, a number setting a lower limit on the bottom, and a number setting an upper limit on the top. Sometimes, there are constants on the outside (to the left) of it. You then plug in each number from the lower limit to the upper limit into the expression and add them up.

A good example would be the binomial theorem. Since I don't know LaTeX, it would be better if someone else did this.

3. May 1, 2004

### lvlastermind

do you know of any links that could expand on this...

4. May 1, 2004

### Integral

Staff Emeritus
Last edited by a moderator: Apr 20, 2017
5. May 1, 2004

### Evgeny

http://mathworld.wolfram.com/Sum.html has some pretty easy explanations on the topic.
You probably want to go over sequences and series before going into sigma-math. After that, things should be pretty clear.

6. May 2, 2004

thanks alot