function [xdot] = sect_5_prob_5_ode_fn(t,x, T,xair,xd,k1,c1,c2)
%   
% 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.
% 
%-----

n = length(x); 
xdot = zeros(n,1); % x = [ x1(t), lambda(t) ]

x1     = x(1); 
lambda = x(2); 

xdot(1) = -(x1 - xair)/T - ( k1^2 / (2*c2) )*lambda;
xdot(2) = lambda/T - 2*c1*( x1 - xd );