% PARAMETERS
b_a = 0.05;
b_b = 0;

r_a = 0.004;
r_b = 0.006;
r_c = 0.0002;

%s   = 0.004;
s = 1;

x0 = [1; 1; 0];

f = @(x) [s * (x(1)^2 + b_a) / (x(1) + x(2)) - r_a*x(1);
          s *  x(1)^2                        - r_b*x(2) + b_b;
          r_c * x(1) - r_c * x(3)];