function sol = prob_4_2(alpha,b,c)
% 
% Written by:
% -- 
% John L. Weatherwax                2005-05-07
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----
  
sol = dde23(@ddes, [7], [alpha], [0, 60],[],b,c);
plot(sol.x,sol.y,'-o');
title( ['alpha=',num2str(alpha),'; b=',num2str(b),'; c=',num2str(c) ] ); 

%==========================================
function dydt = ddes(t,y,Z,b,c)

dydt = [ b*Z(1,1)*(1-y(1)) - c*y(1) ];