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Unformatted text preview: concluding the that the LP is unbounded. This misses the point of the question, which calls for an observation from tableau T 2 . For the proof of unboundedness, there should be two main ingredients: 1. Giving a family of solutions x ( t ) that is feasible for every t 0; 2. Showing that the objective value of x ( t ) tends to as t does. Many students only did (1), which is not enough, since its possible for an LP that is not unbounded to have an unbounded feasible region. Q4: Mistakes: forgetting that the reduced cost c j of a nonbasic variable x j appears with a negative sign in the z-row; Q7: Mistakes: not checking that the solution x * found in item (b) is feasible; assuming that the or in the complementary slackness conditions is exclusive. For instance, y 2 + 2 y 4 > 5 implies that x 2 = 0, but y 2 + 2 y 4 = 5 does not imply that x 2 > 0. 1...
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- Fall '07