Farmer Ed has 2,000 meters of fencing, and wants to enclose a rectangular plot that borders on a river. If Farmer Ed does not fence the side along the river what is the largest area allowed enclosed?

Answer 1

2000m

xy=area=a

2000= 2x+y

y= 2000-2x

a= 2000x-2x^2

a'= 2000-4x=0

x=500m

y=1000m

max area= xy= 500,000 m^2

Answer 2

I gave you the full solution.

Didn't use the camera because... well, I forgot to turn it on!

Answer 3

Area = w(2000 - 2w), deraw and label a diagram!

Detive first derivative, set equal to zero and solve for w.