Calc 1
posted by Grant on .
A farmer with 700 ft of fencing wants to enclose a rectangular area and then divide it into four pens with fencing parallel to one side of the rectangle. What is the largest possible total area of the four pens?

Answer is 12250

so, is there a question somewhere in there?

What is the largest possible total area of the four pens?
Let x=shorter side of the big rectangle.
and y=long side of the big rectangle
Fence required = 5x+2y=700 => y=3505x/2
Total area of pens
A=xy
=x(3505x/2)
To get the maximum area, we equate dA/dx=0
dA/dx = 3505x = 0, or
x=70
y=3505x/2 = 175
Maximum total area=xy=70*175=12250' 
Can someone draw the picture?