Rick has 1200 feet of fence that he wants to use to enclose a rectangular garden. Find the maximum area the garden can have.

Answer 1

I suspect a square
A = L w
L + w = constant = k

L = k - w
so
A = (k-w)w = k w - w^2
dA/dw = k - 2w
= 0 for max or min
so
w = k/2
or w = k = k/2 sure enough a square
so
1200/4 = 300 = L = w
A = 90,000