function [ut]=derv(n,t,u)
%
% Function derv computes the derivative vector
% of the 3 x 3 ODE problem
%
% Problem parameters
  k1=1.0;
  k2=2.0;
%
% Derivative vector
  ut(1)=-k1*u(1);
  ut(2)= k1*u(1)-k2*u(2);
  ut(3)= k2*u(2);
%
% End of derv
