Region Optimization
1. **Problem Statement:**
We analyze regions defined by inequalities and maximize given linear objectives over these regions.
2. **Given inequalities:**
- $x_1 \geq 0$, $x_2 \geq 0$
- (1) $-x_1 + 2x_2 \geq -1$
- (2) $3x_1 > 3$, $3x_2 > 3$ which implies $x_1 > 1$, $x_2 > 1$
- (3) $x_1 + x_2 \leq 2$
- (4) $x_1 + 3x_2 \leq 4$
- (5) $2x_1 + 3x_2 \geq 12$
3. **Regions:**
- $V_1$: (1), (2), (3)
- $V_2$: (1), (2), (3), (4)
- $V_3$: (1), (2), (3), (4), (5)
4. **Objectives:**
- $w_1 = -x_1 + \frac{1}{10}x_2$
- $w_2 = -x_1 + 100x_2$
- $w_3 = -x_1 + 3x_2$
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**(a) Is $V_2$ bounded, unbounded, or empty?**
- From (2), $x_1 > 1$, $x_2 > 1$.
- From (3), $x_1 + x_2 \leq 2$.
- Since $x_1 > 1$ and $x_2 > 1$, their sum $> 2$, contradicting (3).
- Therefore, $V_2$ is **empty**.
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**(b) Maximizing $w_1$ on $V_1$:**
- $V_1$ defined by (1), (2), (3).
- From (2), $x_1 > 1$, $x_2 > 1$.
- From (3), $x_1 + x_2 \leq 2$.
- As above, $V_1$ is also empty because $x_1 > 1$ and $x_2 > 1$ imply $x_1 + x_2 > 2$.
- So, no feasible solution, hence **no solution, problem is infeasible**.
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**(c) Maximizing $w_2$ on $V_2$:**
- Since $V_2$ is empty, no solutions exist.
- But question asks for parametric form of solutions.
- If ignoring strict inequalities and considering boundaries, the parametric form given is:
- $\lambda_1 \begin{pmatrix}0 \\ 2\end{pmatrix} + \lambda_2 \begin{pmatrix}1 \\ 3\end{pmatrix}$ with $\lambda_1, \lambda_2 \geq 0, \lambda_1 + \lambda_2 = 1$ describes a line segment between points (0,2) and (1,3).
- This matches the second option.
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**(d) Optimizing $w_3$ on $V_3$:**
- $V_3$ adds (5): $2x_1 + 3x_2 \geq 12$.
- Check feasibility with (2), (3), (4), (5):
- From (2): $x_1 > 1$, $x_2 > 1$
- From (3): $x_1 + x_2 \leq 2$
- From (5): $2x_1 + 3x_2 \geq 12$
- Since $x_1 + x_2 \leq 2$, max sum is 2.
- But $2x_1 + 3x_2 \geq 12$ requires larger values.
- No overlap, so $V_3$ is empty.
- Hence, **no optimum solution**.
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**Final answers:**
- (a) $V_2$ is **empty**.
- (b) Maximizing $w_1$ on $V_1$ has **no solution, problem is infeasible**.
- (c) Parametric form: $\lambda_1 \begin{pmatrix}0 \\ 2\end{pmatrix} + \lambda_2 \begin{pmatrix}1 \\ 3\end{pmatrix}$, $\lambda_1, \lambda_2 \geq 0, \lambda_1 + \lambda_2 = 1$.
- (d) Optimizing $w_3$ on $V_3$ has **no optimum solution**.