a = 1.6 (slider from -5 to 5, step 0.1)
b = 1.9 (slider from -5 to 5, step 0.1)
c = -0.4 (slider from -5 to 5, step 0.1)
d = -1.1 (slider from -5 to 5, step 0.1)
f(x) = a * exp(b * x + c) + d