To minimize the total length of the fence needed to enclose a rectangular field of 3,000,000 square feet and divide it in half with a fence down the middle, follow these steps:

1. Define the Variables:

   • Let $L$ be the length of the rectangle.
   • Let $W$ be the width of the rectangle.
   • The area of the rectangle is given by: $L \times W = 3,000,000 \quad \text{square feet}$

2. Fence Length Calculation:

   • The total length of the fence will be the perimeter of the rectangle plus the fence down the middle: $\text{Total fence length} = 2L + 3W$

3. Express Width in Terms of Length:

   • From the area constraint: [ W