Introduction: A function of the form $y(x)=a^x$, where $a$ ($a \neq 1)$ is a positive number, is called an exponential function with base $a$.
Definition: The exponential function with base $e$, $y(x)=e^x$, is often found in economic (growth) models. The number $e$ ($\approx 2.718$) is called the number of Euler.
Below a figure of $y(x)=e^x$.
Definition: The exponential function with base $e$, $y(x)=e^x$, is often found in economic (growth) models. The number $e$ ($\approx 2.718$) is called the number of Euler.
Below a figure of $y(x)=e^x$.