derivative

a constant angle 2/m.

one variable), it might be interesting to find the places where local maxima and

minima are located. It is natural, in such a search, to focus on the slope of the

line that is tangent to the function curve, in such a way that local maxima and

minima are found where the slope of the tangent is zero (i.e., the tangent is

horizontal). This operation is possible for all regular functions, which are func-

tions without discontinuities and without sharp corners. Given this assumption

of regularity, the shape of the curve can be defined at any point, thus becom-

ing itself a function of the same independent variable. This function is called

derivative and is indicated with

dx

the tangent line is drawn, two distinct points are taken on this line, the ratio

between the differences of coordinates y and x of the points is formed. As we have

already seen in appendix A.6, this operation corresponds to the computation of

the trigonometric tangent, whose argument is the angle formed by the tangent