The Business Dictionary defines exponential growth as an increase in number or size at a constantly increasing rate. Math Planet explains that exponential growth is represented by an exponential function, which is a nonlinear function with the form, y = ab^x, where a does not equal zero and b is greater than zero. The graph of any exponential growth function rises from left to right in a curved line.
Education Portal adds that growth is exponential if it increases at a consistent rate. One example of exponential growth is found in the human population, where the rate of growth of the number of people in the world increases each year. The multiplying of rabbits, compound financial interest, growth of bacteria, decay of radioactive substances, transmission of disease and the cost of living are real world examples of exponential functions. Boundless suggests that, certainly in terms of human population, exponential growth is possible only when infinite resources are available; therefore, exponential growth cannot continue indefinitely. Limited resources force patterns of growth into the logistic growth model, where growth numbers level off when capacity is reached. Logistic growth is represented by an S-shaped graph and is used to describe phenomena as varied as the uptake of new technology, market saturation and animal extinction events.