a = -0.5 (slider from -10 to 10, step 0.01)
b = 3 (slider from -10 to 10, step 0.1)
c = -2 (slider from -100 to 100, step 0.1)
d: y = a * x * x + b * x + c
DELTA: b * b - 4 * a * c
Xvertice: -(b / (2 * a))
Yvertice: -(DELTA / (4 * a))
V: (Xvertice, Yvertice)
A, B = Intersect(d, xAxis)
C = Intersect(d, yAxis)
e: y = -1 * (1 + DELTA) / (4 * a)
F: (Xvertice, (1 - DELTA) / (4 * a))
D = Point(d)
f = Segment(D, F)
g = OrthogonalLine(D, e)
E = Intersect(g, e)
h = Segment(D, E)