Exponential functions, it's a lot different from polynomial functions. For example lets look at the graph above, there is something different than your usual polynomial function, here is an example of one, 3x^2 - x - 5 when we compare that equation to f(x) = 2^x we see a difference in the exponential function the variable x is represented as an exponent. This is the major difference between these two equation as the exponential function can be seen as a rise or a fall. Well how is this information useful? Well with exponential functions we can see when we graph it it can be represented as a rise or a fall, so with this information we could use different medicines to see how fast they can kill bacteria and how long it takes to kill everything. This is great for the medical field right now as cancer is the main priority to find a cure for, we could use different medicines to see how fast they kill tumors, to see if they can kill it fast enough before it's too late. This would be seen as a fall when you graph it, for rise we could use population growth and predict what the population would be, this would be essential to see how big the population would be in a city to see if it's necessary to continue building apartments houses, etc. To see what should the government fund towards and population growth can also predict some problems such as traffic in roads, so to see if it's necessary to continue building more roads.