## Sigma

I think this is the right forum. I wondering how "sigma" is used, the definition is summation but what does that mean, is it just the sum? Can some 1 give me an example of how it works. Thnx.
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 $$\sum^{n}_{i=0} f(i)$$ This is the sum of f(i) from i=0 to i=n, i.e. f(0) + f(1) + f(2) + ... f(n)
 Recognitions: Homework Help Science Advisor If you are referring to sigma notation (with the Greek letter $\Sigma$). It's a convenient way of writing sums. Suppose you have a sequence of numbers $a_m,a_{m+1},...,a_n$ and you want to add them, then: $$\sum_{i=m}^na_i=a_m+a_{m+1}+...+a_n$$ The $i$ is a variable used for counting. The $i=m$ at the bottom tells us to start with $i=m$ and the $n$ at the top tells us to end with $i=n$. For example: $$\sum_{i=1}^7 i= 1+2+3+4+5+6+7$$ $$\sum_{i=5}^9 i^2= 5^2+6^2+7^2+8^2+9^2$$ $$\sum_{j=0}^5 2^j=2^0+2^1+2^2+2^3+2^4+2^5$$ etc.

## Sigma

lol i kinda see it but its a bit unclear to me, maybe a simpler example lol thnx
 lol thnx galileo i see it