# How do you graph exponential decay functions?

This is an example for the function $f \left(x\right) = 2 \cdot {e}^{- 3 x}$
This is just a particular case of the general form $f \left(x\right) = a \cdot {e}^{k x}$
where $a$ is a constant representing the value at start and $k$ is the rate of growth (when $k > 0$) or the rate of decay (when $k < 0$).
(Please note that $f$ is always a function of time, so the symbol $t$ it is often used instead of $x$).