A = (0, 20)
B = (3, 100)
C = (4, 90)
a = 1 (slider from -5 to 5, step 0.1)
c = -2.4 (slider from -5 to 5, step 0.1)
b = 1 (slider from -5 to 5, step 0.1)
D = (1, 85)
Liste1: {A, B, C, D}
f = Fit(Liste1, a * (x + b) * exp(x / c))