A farmer has 320 m of fencing to enclose a rectangular field along a straight river. No fence is needed along the river. Find the length y of the side parallel to the river for the largest area.
Optimization worksheet with answers
A rectangular pen is fenced with 360 m of fencing and divided into two parts by one extra fence parallel to the sides of length x (three fences of length x and two of length y in total). Find the largest total area A that can be enclosed.
A closed cylindrical can (with a top and a bottom) must hold 330 cm³. The metal used is proportional to the total surface area. Find the smallest possible surface area A.
A closed cylindrical can (with a top and a bottom) must hold 330 cm³. The metal used is proportional to the total surface area. Find the radius r that uses the least material.
A company sells q units per week. The price at which it can sell them is p = 180 − 0.25q euros per unit, and the cost is C(q) = 9600 + 25q euros. Find the maximum weekly profit P.
A company sells q units per week. The price at which it can sell them is p = 90 − 2q euros per unit, and the cost is C(q) = 200 + 15q euros. Find the maximum weekly profit P.
Answer key
- 1. y = 160 m
- 2. A = 5400 m²
- 3. A = 264.4 cm²
- 4. r = 3.745 cm
- 5. P = 14425 €
- 6. P = 503.1 €
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