Figuring out how to compute average period growth rate given start size, end size, and number of periods.

growth.md

g = period growth rate, eg, % MOM growth
S = starting size
E = ending size
n = number of periods elapsed between S and E

We know that to compute E from S, g, and n, we can use the equation:

E = S * (1 + g) ^ n

Let's do some algebra to transform this into an equation that solves for g when the other variables are known:

E = S * (1 + g) ^ n

E/S = (1 + g) ^ n

log10(E/S)  = n * log10(1 + g)

log10(E/S) / n = log10(1 + g)

10 ^ (log10(E/S) / n) = 1 + g

g = 10 ^ (log10(E/S) / n) - 1