Posted by Chris on Friday, December 16, 2011 at 5:54am.
Damon help again :) (last one I promise)
why is X along the road sqrt2/2?
] A rancher plans to set aside a rectangular region of one square kilometer for cattle and wishes to build a wooden fence to enclose the region. Since one side of the region will run along the road, the rancher decides to use a better quality wood for that side which costs three times as much as the wood for the other sides. What dimensions will minimize the cost of the fence?
x y = 1
c = 3 x + x + 2 y = 4 x + 2 y
c = 4 x + 2/x
dc/dx = 4  2/x^2
= 0 for minimum
4 = 2/x^2
x^2 = 1/2
x = 1/sqrt 2 = sqrt 2/2 along road
y = sqrt 2

calculus  drwls, Friday, December 16, 2011 at 6:13am
This question has already been answered by Damon

calculus  Chris, Friday, December 16, 2011 at 6:16am
Yes, I know, but I i had question about the answer... I'm math stupid :)

calculus  Damon, Friday, December 16, 2011 at 8:37am
The smaller of x or y will be the expensive fence along the road.