f(x) = 1.0 / x
g(x) = 1.0 / (x - 2.0)
h(x) = 1.0 / (x - 3.0)
a = -3.8 (slider from -5 to 5, step 0.1)
i(x) = 1.0 / (x - 1.0)
j(x) = 1.0 / (x - a)
b: x = a