G = 10 (slider from -5 to 20, step 0.1)
k: 0.05
a = 2 (slider from -5 to 5, step 0.1)
f(x) = (G * 1 / (1 + (ℯ^((((-k) * G) * x)) * (G / a - 1))))
h(x) = ln(f(x))