function cdot = ex42(t, c)
% 
% this file defines the differential equation set (4.2.8) - (4.2.11), 
% Ca=c(1), Cb=c(2), Cc=c(3), Cab=cc(4).
%

alpha = 8;
beta = 10^4;

cdot(1,:) = -c(1,:)-beta*c(1,:)*c(2,:);
cdot(2,:) = c(1,:)-beta*c(1,:)*c(2,:)+2*alpha*c(4,:);
cdot(3,:) = c(1,:)+alpha*c(4,:);
cdot(4,:) = beta*c(1,:)*c(2,:)-alpha*c(4,:);
