Mathematical symbols .

[swannbaker]

To express 120 in mathematical terms , I can use the symbol ! with 5 , i.e. the product of all the positive integers less than or equal to 5 .
What symbol can I use to express 15 in terms of 5 , i.e. the sum of those same integers ?

[bibblebub]

1+2+3+4+5

[bibblebub]

or capital sigma Σ

[roslyn251254]

a sigma sign (greek for sum of)?

[factor-fiction]

You need the ∑ symbol. I can't type it on AB but you need ∑n with n=0 at the bottom and 5 at the top of the sigma. you also need to make it clear that n belongs to teh group of integers

[mibn2cweus]

Big Sigma & Big Pi: http://www.mathlesstraveled.com/?page_id=50

[mike11111]

Σn means the sum of the numbers from 1 to n so Σ5 = 15, Σ6 = 21 etc.

[Prudie]

Mike I beg to diiffer and earlier answers are correct. It needs ∑n with the limits at top and bottom ie n=1 and n=5

[factor-fiction]

Not quite right, mike11111.
Σ5 just means 5+5+5+5+....
The sigma notation of Σn also needs to specify the first and last value of n. In this case it would have to say n=1 under the sigma sign and the last value of n (in this case 5) would be shown above the sigma sign.
(I think it may also be necessary to make it clear that n comes from the set of integers)

[factor-fiction]

5
∑k
k=1

The sum of integers 1 to n can also calculated thus:
n(n+1)/2
eg 1+2+3+4+5= 5 x 6 / 2 = 15

[swannbaker]

Many thanks to all . I think .

[Prudie]

I can promise you swannie that factor 30's answers are 100% correct - honest!