a = -2.22 (slider from -3 to 0, step 0.001)
b: y^(4) + x^(4) + 2 * x^(2) * y^(2) + 2 * a * y^(2) - 2 * x^(2) + 1 = 0
f(x) = (cos(x)^(2) + 1) / (cos(x)^(2) - 1)