Question: I am trying to integrate a version/source control system with my unity project. [This answer](http://answers.unity3d.com/answers/1251608/view.html) directed me towards using source/version control. (I dont know the difference.) 

The answer links to a tutorial which explains creating the repository and pushing it to a remote service. I followed the whole tutorial. But I still don't understand how this integrates with my current projects.

My question is that.

1. how can I do this locally
2. how will this make it possible to revert to previously-saved versions?

Answer: 
its very simple, since i<=($n+2) the total iterations will be 4.
for first iteration, 

```
$i=1 the value of s = 0+(2*1+5) = 7
$i=2 now s = 7+(2*2+5) = 16
$i=3 now s = 16+(2*3+5) = 27
$i=4 now s = 27+(2*4+5) = 40

```

Hope this explains.
This is simple math. s is the sum of for i from 1 to n+2 of 2i+a. This is equal to the twice sum of i plus the sum of a. The latter is clearly worth (n+2)a. The former is twice the sum of integers from 1 to n+2, i.e. 2 \* (n+2)(n+3)/2. The total is thus (n+2)(n+3) + (n+2)a = (n+2)(n+3+a) = (2+2)\*(2+3+5) = 4\*10 = 40. (Side effect: no need to have an explicit loop, just implement the above formula.)