function yp = sect_2_3_prob_4_eq(x,t,params)
% SECT_2_3_PROB_4_EQ - returns dy/dt for this problem
%   
% Written by:
% -- 
% John L. Weatherwax                2006-08-28
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

u = 1; % the control (taken as a constant)

M = [ -0.5, 1; 0, -0.7 ];
yp = M * x(:) + [0;1]*u;