Farmer Ed has 950 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, find the length and width of the plot that will maximize the area. What is the largest area that can be​ enclosed?

Respuesta :

The perimeter for this case is given by:

[tex] P = y + 2x
[/tex]

Substituting values we have:

[tex] y + 2x = 950
[/tex]

The area is given by:

[tex] A = x * y
[/tex]

Writing the area based on a variable we have:

[tex] A (x) = x * (950 - 2x)

A (x) = -2x ^ 2 + 950x
[/tex]

We derive the area to obtain the maximum of the function:

[tex] A '(x) = -4x + 950
[/tex]

We equal zero and clear x:

[tex] -4x + 950 = 0

4x = 950

x = 950/4

x = 237.5
[/tex]

Then, the other dimension is given by:

[tex] y = 950 - 2x

y = 950 - 2 * (237.5)

y = 475
[/tex]

Finally the maximum area is:

[tex] A = (237.5) * (475)

A = 112812.5 m ^ 2
[/tex]

Answer:

The length and width of the plot that will maximize the area are:

[tex] x = 237.5 m

y = 475 m
[/tex]

The largest area that can be enclosed is:

[tex] A = 112812.5 m ^ 2 [/tex]