function [ydot] = sect_6_1_extended_kf_fn(t,y, k_1,k_2,k_3u,mu_q,var_q)
%
% Inputs: 
%
% Written by:
% -- 
% John L. Weatherwax                2005-08-14
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

ydot = zeros(2,1);

x = y(1);
p = y(2);

ydot(1) = -k_1*x - k_2*x^4 + k_3u + mu_q;
ydot(2) = 2*(-k_1 - 4*k_2*x^3)*p + var_q;