Consider the model without nonnegativity constraints given in Prob. 4.6-14.
(a) Construct its dual problem.
(b) Demonstrate that the answer in part (a) is correct (i.e., variables without nonnegativity constraints yield equality constraints in the dual problem) by first converting the primal problem to our standard form (see Table 6.12), then constructing its dual problem, and finally converting this dual problem to the form obtained in part (a).