grafico \; di \; \; f\;'(x) \; = \; \frac{ f(x+h)-f(x) }{h } 

A = Point(xAxis)
f(x) = sin(x)
a = OrthogonalLine(A, xAxis)
P = Intersect(f, a, (0.5, 0.479425538604203))
h = 0.0010 (slider from 0 to 1, step 0.0010)
A': (x(A) + h, 0)
b = OrthogonalLine(A', xAxis)
C = Intersect(f, b, (0.501, 0.4803028813070803))
d = Line(P, C)
c = OrthogonalLine(P, a)
D = Intersect(b, c)
e = Segment(P, D)
g = Segment(D, C)
E = (-1, 0)
i = Line(E, d)
F = Intersect(i, yAxis)
j = Segment(A, P)
l = Line(F, xAxis)
P' = Intersect(l, a)
m = Segment(F, P')
f' = Locus(P', A)
B: (x(A) + 1, 0)
n = OrthogonalLine(B, xAxis)
G = Intersect(n, d)
u = Vector(P, G)
v = Vector(E, F)
k = Segment(A, P')
pendenza = Vector((0, 0), F)