Suppose that a curve is the graph of a function f(x). It is usually possible to obtain a formula that gives the slope of the curve y = f(x) at any point. This slope formula is called the derivative of f(x) and written f'(x). For each value of x , f'(x) gives the slope of the curve
y =f(x) at point with first coordinate x.
Next: The Derivatve(cont.1)