In exponential growth, the rate of growth is proportional to the quantity present. In other words, y′=ky. Systems that exhibit exponential growth have a constant doubling time, which is given by (ln2)/k. Systems that exhibit exponential decay have a constant half-life, which is given by (ln2)/k
In some cases with exponential functions, as the value of x increases, the value of y also increases. This is a direct relationship known as exponential growth. As the value of x increases, the value of y grows rapidly. ... This is an inverse relationship known as decay.
