function xprime = rabfox(t,x)
% rabfox: System of 2 ODE for the rabbits and foxes
% predator-prey problem.
% t is the time
% x(1) is the rabbit population at time t
% x(2) is the fox population at time t
% The system is
% x(1)' = 2x(1) - 2x(1)x(2)
% x(2)' = -x(2) + x(1)x(2)
%
% the right hand sides are returned as a column vector
% since ode45 requires a column vector

   xprime = [2*x(1) - 2*x(1)*x(2); -x(2) + x(1)*x(2)];
   
end