I know there is a built-in function for that but can't remember what it is.

Let's say I have a number, `10`

, and over a period of a year that number has increased by `100%`

to `20`

. I would like to figure out what the monthly increase should be for `10`

to reach `20`

over `12`

months.

If I convert `100%`

to a coefficient I get `2`

. Now by trying several numbers manually I figured the monthly coefficient should be around `1.065`

:

```
M. NUMBER COEFF
1 10 1.065
2 10.65 1.065
3 11.34225 1.065
4 12.07949625 1.065
5 12.8646635063 1.065
6 13.7008666342 1.065
7 14.5914229654 1.065
8 15.5398654581 1.065
9 16.5499567129 1.065
10 17.6257038992 1.065
11 18.7713746527 1.065
12 19.9915140051 1.065
```

**Q: How can I obtain the monthly coefficient (something around 1.065) from 2 and 12?**