I am trying to figure something out, but for some reason I keep hitting a brick wall. Any help would be VERY much appreciated!
I'm working on a spreadsheet right now for a fundraising thing. And basically, I need to know if there is any way to simplify what I'm trying to do.
With factorials, you're dealing with the PRODUCT of an integer and all the non-negative integers less than it. What I need to know is if there is any way to express the SUM of the integers. Like 5+4+3+2+1=15.
If that makes any sense at all, I'd appreciate any help. Thanks!
2007-10-04 06:50:46 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
if you want to sum up all the positive integers from 1 to n then the formula is n*(n+1)/2. it is derieved from arithmetic progression.
2007-10-04 06:55:09 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Sum of integers is the Sum of Arithmetic Progression. It is given by
Sum of n terms = n/2 (first term + last term)
2007-10-04 07:00:23 · answer #2 · answered by Swamy 7 · 0⤊ 0⤋
if you want to find the sum of a number N and all the numbers that led up to it starting from 1, then take 1/2 of the product of your last term N and N+1.
Example:
to add the numbers from 100 to 1 and get their sum:
(1/2)(100*(100+1))= 5050
2007-10-04 07:22:22 · answer #3 · answered by 037 G 6 · 0⤊ 0⤋
Just use the formula for the sum of an arithmetic progression.
2007-10-04 06:58:38 · answer #4 · answered by ironduke8159 7 · 0⤊ 0⤋
What you are looking for is often referred to as the 'triangle' (as opposed to the square) of a number. This can be found by adding the number to the square of itself and dividing the result by 2; i.e. the formula is T=(N+N^2)/2.
I hope this helps, but please feel free to drop me a line if you'd like to discuss this (or any other figure-work) further.
2007-10-04 07:16:59 · answer #5 · answered by general_ego 3 · 0⤊ 0⤋