Draw variants of Fig. C.1 which show that solutions may exist when the objective function is discontinuous, and the feasible set open and unbounded. From this, explain what is meant by the statement...

Draw variants of Fig. C.1 which show that solutions may exist when the objective function is discontinuous, and the feasible set open and unbounded. From this, explain what is meant by the statement that the conditions of the existence theorem are sufficient but not necessary.