f(z) = az/(Pi^2 - 4z) cos(sqrt(z)) a = 19.739209 -20.000000 < x < 60.000000 -40.000000 < y < 40.000000 pixcel: 400 x 400 margin: 20 maximal iteration: 500 parabolic fixed point: (9.869604, 0.000000)