ABSTRACT
The smaller we make x, the closer the calculation of slope is to the slope of the tangent at x. That is, expressed as a limit:
The slope, or the rate of change of y with respect to x, is called the derivative of y with respect to x. There are various forms of notation for expressing the derivative:
Not all functions are differentiable. For the derivative of a function to exist at x, the function must be continuous at x. However, not all functions which are continuous can be differentiated.
