A = (-4, -5, -2)
B = (0, -5, -2)
E = (0, 0, 4)
α = 0.13 (slider from -5 to 5, step 0.01)
P: A + (α * (E - A))
a_1 = Line(A, E)
u = Vector(A, P)
O = Intersect(zAxis, xAxis)
a = Vector(O, A)