function xdot =xprime(t,x,k)
%function xdot =xprime(t,x,k)
% this vers of xprime for use with new ode45k from ode suite
% example ode fitting


%Arthur Jutan 
%Dept of Chemical and Biochemical Enginering
%Univ of Western Ontario
%London Ontario Canada, N6A 5B9

xdot(1)=-k(1).* x(1) - k(2).*x(2);
xdot(2)= k(1)*x(1) +k(2).*x(2);
% make sure output is a col vector
xdot=xdot(:);
return

