A = (0, 0)
B = (2, 4)
u = Vector(A, B)
C = (3.5, 0.5)
v = Vector(A, C)
D = Point(v)
w = Vector(D, B)
z = Vector(A, D)
skalarptoduktzw: (z * w)
λ: Length[z] / Length[v]