Differentiation Definition

Differentiation is rate of change of a parameter. Usually we find the rate of change of x with respect to function f(x). 

If we have a straight line, the rate of change simply is the gradient!

But if we have a curve, the gradient varies from point to point. So we need to draw a tangent to the curve at any point that we need the gradient. But this can be tedious. We can also find a mathematical expression of the gradient and this is the differentiation!