t_D = 20 (slider from -5 to 20, step 0.05)
A: 80
f(x) = (A * 0.5^(x / t_D))
rob = 0 (slider from 0 to 80, step 20)
B: (rob, f(rob))
a = Line(B, xAxis)
BM: (rob, y(B) / 2)
b = Line(BM, xAxis)
C = Intersect(f, b, (19.999999999999996, 40.00000000000001))
c = Segment(B, BM)
B0: (rob, 0)
d = Segment(BM, B0)
e = Segment(BM, C)