w(t) = 500/(625 + (t - 40)^2) = 500/(t^2 - 80·t + 2225)
W(t) = 20·ATAN((t - 40)/25) + 20.74394022
a)
W(100) = 44.26 m
b)
w''(t) = 1000·(3·t^2 - 240·t + 4175)/(t^2 - 80·t + 2225)^3 = 0 --> t = 25.57 Jahre [∨ t = 54.43]
c)
w'(t) = 1000·(40 - t)/(t^2 - 80·t + 2225)^2 = 0 --> t = 40 Jahre