Exponential functions are used to predict a certain result that can possibly be drawn based on repetitive patterns. These functions can be usefully applied to our daily lives since everything that happens in our society is a result of a certain pattern and as long as calculating the pattern and trying to deal with such variances and frequencies in order to lead a better life style is part of a human instinct, prediction of a pattern is necessary to avoid possible risks. Exponential functions can be used in a various situation. For instance, when someone who deposited $300 to a bank which provides 5% annual interests wants to figure out how much money he/she can earn after a decade, exponential functions make it easy to calculate. The answer is 300(1.05)^10. The equation of the function is y=ab^t ( a represents the initial amount and b is a factor) which represents growth (premise: when a>0 and b>1) and decay (premise: when a>0 and 0<b<1). This example is an epitome of the former one.