A farmer will fence three sides of a rectangular pen adjacent to a straight river
MATHEMATICS · Subjective · CBSE · Mathematics · Applications of Derivatives · Applications of Derivatives
Problem
A farmer will fence three sides of a rectangular pen adjacent to a straight river, leaving the side along the river unfenced. The side parallel to the river uses reinforced fencing costing 18 dollars per meter, while the two perpendicular sides use standard fencing costing 10 dollars per meter each. The farmer can spend at most 720 dollars on fencing. Let w denote the width of the pen perpendicular to the river. Determine the value of w, in meters, that maximizes the enclosed area.