f(x) = ((-x^(2)) + (4 * x) + 12) / ((2 * x))
a = 4.3 (slider from 0 to 6, step 0.05)
X: (a, 0)
Y: (0, f(a))
M: (a, f(a))
O: (0, 0)
poly1, o, XM, m, B = Polygon(O, X, M, Y)
A: (a, poly1)