Norme d'un vecteur
Author: Mentrard
Date: 2008

 \ |  |\vec{AB} |  |= \sqrt {( x(B) - x(A)) \ {^2}+  ( y(B) - y(A)) \ {^2}  }

A = (0, 0)
B = (9, 5)
u = Vector(A, B)
T1: " \ |  |\vec{AB} |  | = \sqrt {(" + (x(u)) + ")\ {^2}" + "+ (" + (y(u)) + ")\ {^2}" + "}" + " = " + (Length[u])
T2: "\vec{AB} {" + (x(u)) + "\choose" + (y(u)) + "}"
b = OrthogonalLine(B, xAxis)
c = OrthogonalLine(A, yAxis)
C = Intersect(b, c)
d = Segment(B, C)
e = Segment(C, A)
D = Intersect(xAxis, yAxis)
E = Point(xAxis)
F = Point(yAxis)
j = Vector(D, F)
i = Vector(D, E)
f = Segment(A, B)
T4: "x(B)-x(A)=" + (x(u))
T5: "y(B)-y(A)=" + (y(u))