The derivative is a measure of how a function changes as its input changes. Derivative is also the rate of change of function(f) with respect to variable(x), as the variable changes from x to x + h (where h approaches to zero). The process of finding a derivative is called differentiation. We shall study in detail the meaning and the process of differentiation. Its found that the concept of differentiation has been applied to many other fields as well. This section will help us to understand the concept of differentiation.