# How do I use the summation symbol? I want to use the summation symbol (capital Delta from i=-2 to 2) but I can't figure out how to get the 2 on top of the capital Delta.

## Asking on behalf of T. Michael B.. Thanks!

Jul 15, 2016

Type

hashtag "sum^2" hashtag

This looks like:

${\sum}^{2}$

#### Explanation:

Hopefully this is what you're trying to achieve.

Jul 15, 2016

Here's how you can do that.

#### Explanation:

To expand a little on the answer given by Acquaintance, the summation symbol, which as far as I know is capital sigma, $\sum$, not capital delta, $\Delta$, works exactly as any other character, i.e. it can take subscripts and superscripts.

Now, the thing to remember about the summation symbol is that although you can use capital sigma, "Sigma", which gives you $\Sigma$, it's better to go for "sum", which gives you $\sum$.

So, for example, you can write

• without hashtags

Sigma

• with hashtags

$\Sigma$

On the other hand, you can write

• without hashtags

sum

• with hashtags

$\sum$

Now, you can add subscripts and superscripts to the "sum" symbol by using the "_" and "^" characters.

For example, you can write

• without the hashtags

sum_(i=-2)^2 "whatever"

• with hashtags

${\sum}_{i = - 2}^{2} \text{whatever}$

In this example, the subscript, $i = - 2$, is added by using the "_" character and parentheses. The superscript, $2$, is added by using the "^" character.

So, to sum this up, you can add subscripts and superscripts to the "sum" symbol by using the "_" and "^" characters.

Another example would be

• without hashtags

sum_(n=0)^(oo) n^2

• with hashtags

${\sum}_{n = 0}^{\infty} {n}^{2}$