O = Point(a)
U = Point(a)
u = Vector(O, U)
A = Point(a)
v = Vector(O, A)
b: x(A) - x(O)
c: x(U) - x(O)
d: b / c
e = OrthogonalLine(A, a)
f = OrthogonalLine(U, a)
g = OrthogonalLine(O, a)
B = Point(g)
h = Line(B, a)
C = Intersect(e, h)
w = Vector(B, C)
i = Segment(B, C)
j = Segment(O, B)
D = Point(g)
k = Line(D, a)
E = Intersect(e, k)
F = Midpoint(B, C)
l = Segment(E, A)
m = Segment(D, O)
texto1: "a=" + (LaTeX[d]) + ""