appliedcalculus
posted by Anonymous .
Suppose a farmer has 1,000 feet of fence and wishes to build two identical rectangular enclosures. What should be the dimensions of each enclosure if the total area is to be a maximum?
Set problem up and solve using derivatives.

if the sides are x,y
a = 2xy
now, 4x+4y=1000, so y=250x and so
a = 2x(250x) = 500x  2x^2
da/dx = 5004x
da/dx=0 when x=125
so, the enclosures are both squares, 125x125