The perimeter is given by:
P = 2x + 2y = 28
The area is given by:
A = x * y
Writing the area based on x we have:
A (x) = x * (14-x)
Rewriting:
A (x) = 14x-x ^ 2
Deriving we have:
A '(x) = 14-2x
We equal zero and clear x:
14-2x = 0
x = 14/2
x = 7
We are now looking for the other dimension:
y = 14-x
y = 14-7
y = 7
Answer: The length and width of a rectangle that has the given perimeter and a maximum area are:
y = 7 meters
