When it comes to mathematical function, logarithmic and exponential functions are important for both theory and practice. A function of the form f(x) = ax (where a > 0) is called an exponential function. The function f(x) = 1x is just the constant function f(x) = 1. A function of the form f(x) = loga x (where a > 0 and a ¹ 1) is called a logarithm function. The function f(x) = loga x for a > 1 has a graph which is close to the negative f(x)-axis for x < 1 and increases slowly for positive x. The exponential function f(x) = e x is the inverse of the logarithm function f(x) = ln x. These two functions can be applied to different real-world problems, namely probability distribution. Besides, the relationship between x and y can be plotted in an x-y coordinating system which can visualize the trend better.