The function $$y=e^x$$ is one-to-one, and therefore its inverse function is not defined.

Exponential functions are often used to model situations in which change occurs continuously at a rate proportional to the current amount.

Exponential functions have a rate of change that is proportional to the current value, leading to continuous growth or decay.

The natural logarithm function $$\ln(x)$$ is the inverse of the exponential function $$e^x$$.