A variable undergoing logistic growth initially grows exponentially. After some time, the rate of growth decreases and the function levels off, forming a sigmoid, or s-shaped curve. For example ...

Substituting this Figure for the f(N) (which is the function that the intrinsic rate of increase is) gives us our final result, the famous logistic equation that describes logistic population growth.

This is called a logistic function. Here’s how it works: At the start of the outbreak, N is very small. ... Reduce the growth rate, stretch out the curve, and you save lives.

The formula for exponential growth is V = S x (1+R) T, where S is the starting value, R is the interest rate, T is the number of periods that have elapsed, and V is the current value.