# Calculus

A rancher wants to make a rectangular pen to house her animals. She will divide it up with 3 fences down the middle parallel to one side. If she has 14000 ft of fencing to work with, what are the dimensions of the pen of greatest area?
Width =
Length =

What is the greatest area pen that the rancher can make?
Area =

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1. 2x+5y=14000
a = xy = x(14000-2x)/5
da/dx = 2800 - 4x/5
da/dx=0 when x = 3500

so, the pen is 3500x1400

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