ศัพท์ทางคณิตศาสตร์In the starting tableau, both Xl and X2 have negative z-equation coefficients. Hence either
one can improve the solution. Because Xl has the most negative coefficient, it is normally selected as the entering variable. However, all the constraint coefficients under X2 (Le., the denominators of the ratios of the feasibility condition) are negative or zero. This means that there is no
leaving variable and that X2 can be increased indefinitely without violating any ofthe constraints
(compare with the graphical interpretation of the minimum ratio in Figure 3.5). Because each
unit increase in Xl will increase z by 1, an infinite increase in X2 leads to an infinite increase in z.
Thus, the problem has no bounded solution. This result can be seen in Figure 3.10. The solution
space is unbounded in the direction of X2, and the value ofz can be increased indefinitely.
Remarks. What would have happened if we had applied the strict optimality condition that
calls for Xl to enter the solution? The answer is that a succeeding tableau would eventually have
led to an entering variable with the same characteristics as X2' See Problem 1, Set3.5c.