$C$

$B(1,0)$

$A$

$\vec v=(0,-1)$

a = 2 (slider from -10 to 10, step 0.1)
C: (a + 1, 0)
B: (1, 0)
v = Vector(B, C)
A: (0, 0)
u = Vector(A, C)
d2: u / v
M: (a + 1, x(d2))
D = Intersect(xAxis, yAxis)
text1 = SurdText(x(d2))
text2: "(ABC)=" + (LaTeX[text1]) + ""
GMB3 = Locus(M, a)
f = OrthogonalLine(B, xAxis)
w = Vector(C, M)
text3 = SurdText(M)
text4 = SurdText(x(M))
text5: "\vec v=\left( " + (LaTeX[text4]) + "," + (LaTeX[text1]) + "  \right) "
E = Midpoint(C, M)