Lp Primal Dual 565201
1. **Problem Statement:**
We have two crops, Maize and Soybean, with constraints on land, labor, and nitrogen resources. We want to maximize returns.
2. **Define Variables:**
Let $X_1$ = area (ha) for Maize
Let $X_2$ = area (ha) for Soybean
3. **Formulate the Primal Problem:**
Maximize returns:
$$\text{Maximize } Z = 3600X_1 + 3000X_2$$
Subject to resource constraints:
- Land: $$X_1 + X_2 \leq 5$$
- Labor: $$10X_1 + 25X_2 \leq 100$$
- Nitrogen: $$80X_1 + 25X_2 \leq 320$$
- Non-negativity: $$X_1 \geq 0, X_2 \geq 0$$
4. **Formulate the Dual Problem:**
Let $Y_1, Y_2, Y_3$ be the dual variables for land, labor, and nitrogen constraints respectively.
Minimize:
$$W = 5Y_1 + 100Y_2 + 320Y_3$$
Subject to:
- For Maize: $$Y_1 + 10Y_2 + 80Y_3 \geq 3600$$
- For Soybean: $$Y_1 + 25Y_2 + 25Y_3 \geq 3000$$
- Non-negativity: $$Y_1, Y_2, Y_3 \geq 0$$
5. **Graphic Solution for Primal:**
Plot the constraints:
- $$X_1 + X_2 = 5$$
- $$10X_1 + 25X_2 = 100$$
- $$80X_1 + 25X_2 = 320$$
Find feasible region in the first quadrant and evaluate $Z$ at vertices.
6. **Graphic Solution for Dual:**
Plot inequalities:
- $$Y_1 + 10Y_2 + 80Y_3 \geq 3600$$
- $$Y_1 + 25Y_2 + 25Y_3 \geq 3000$$
With $$Y_1, Y_2, Y_3 \geq 0$$
Find feasible region and minimize $W$.
**Final answers:**
- Primal:
$$\max Z = 3600X_1 + 3000X_2$$
subject to
$$X_1 + X_2 \leq 5$$
$$10X_1 + 25X_2 \leq 100$$
$$80X_1 + 25X_2 \leq 320$$
$$X_1, X_2 \geq 0$$
- Dual:
$$\min W = 5Y_1 + 100Y_2 + 320Y_3$$
subject to
$$Y_1 + 10Y_2 + 80Y_3 \geq 3600$$
$$Y_1 + 25Y_2 + 25Y_3 \geq 3000$$
$$Y_1, Y_2, Y_3 \geq 0$$