The exponential function is a function in mathematics. The
application of this function to a value x is written as exp(x).
Equivalently, this can be written in the form ex,
where e is a mathematical constant, the base of the natural
logarithm, which equals approximately 2.718281828, and is
also known as Euler's number.
a population of bacteria doubles in size every hour. If its
population was 100 when first seen, then population P after
t hours will be given by P = 100 x 2t.
Any function which involves a power as seen above is called
an exponential function. Another example is the amount £A
accumulated after n years from investing £500 at 6%
compound interest. A= 500 x 1.062.