function res = chap_9_prob_3_mu(n,s,mu)
% CHAP_9_PROB_3_MU - 
% 
% Written by:
% -- 
% John L. Weatherwax                2007-09-10
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

if( n <= s )
  res = mu*n + 1e-6;        % <- add small offset so res>0 (but very small)
else
  res = mu*s; 
end

return;