Get comprehensive answers to your questions with the help of IDNLearn.com's community. Discover reliable and timely information on any topic from our network of experienced professionals.

You have land that you would like to use to create two distinct fenced-in areas in the shape given below. You have 410 meters of fencing materials to use. What values of x and y would result in the maximum area that you can enclose

Sagot :

Answer:

[tex]x = \frac{205}{3}[/tex]

[tex]y =\frac{195}{4}[/tex]

Step-by-step explanation:

Given

[tex]p = 410[/tex] --- perimeter

See attachment for fence

Required

x and y

The perimeter of the fence is:

[tex]p = 2(x + y +5 + y) +x[/tex]

Open bracket

[tex]p = 2x + 2y +10 + 2y +x[/tex]

Collect like terms

[tex]p = 2x+x + 2y + 2y+10[/tex]

[tex]p = 3x + 4y+10[/tex]

Substitute: [tex]p = 410[/tex]

[tex]3x + 4y+10 =410[/tex]

Make 4y the subject

[tex]4y =410-10-3x[/tex]

[tex]4y =400-3x[/tex]

Make y the subject

[tex]y =\frac{400-3x}{4}[/tex]

The area (A) of the fence is:

[tex]A = (y + y + 5) * x[/tex]

[tex]A = (2y + 5) * x[/tex]

Substitute: [tex]y =\frac{400-3x}{4}[/tex]

[tex]A = (2*\frac{400-3x}{4} + 5) * x[/tex]

[tex]A = (\frac{400-3x}{2} + 5) * x[/tex]

Take LCM

[tex]A = (\frac{400-3x+10}{2}) * x[/tex]

Solve like terms

[tex]A = (\frac{410-3x}{2}) * x[/tex]

Open bracket

[tex]A = \frac{410x-3x^2}{2}[/tex]

Remove fraction

[tex]A = 205x-1.5x^2[/tex]

Differentiate both sides

[tex]A' = 205 - 3x[/tex]

To maximize; set [tex]A' =0[/tex]

[tex]205 - 3x =0[/tex]

Solve for 3x

[tex]3x = 205[/tex]

Solve for x

[tex]x = \frac{205}{3}[/tex]

Recall that: [tex]y =\frac{400-3x}{4}[/tex]

So, we have:

[tex]y =\frac{400-3*205/3}{4}[/tex]

[tex]y =\frac{400-205}{4}[/tex]

[tex]y =\frac{195}{4}[/tex]

View image MrRoyal