Exponential functions are functions which contains terms which are integers raised to the power of variables. Note that the variables are not raised to the power of integers, but the integers are raised to the power of variables. Variables raised to the power of integers are called as polynomials and are a different class of functions. But exponential functions grow very fast than polynomials with the increase in the value of the variable. To understand the growth of these functions take a simple equation like y equals to 3 raised to the power of x. Now make a chart with values of x and y. Substitute x with values in increasing order and observe the value of y. You can notice how fast the value of y grows. This video shows the exponential functions and their growth.