rectangles beneath a semicircle a rectangle is constructed with its base on the diameter of a semicircle with radius 5 and its two other vertices on the semicircle. what are the dimensions of the rectangle with maximum area

Respuesta :

Using the area of rectangle, the dimensions of the rectangle with maximum area are 5√2 and 5/√2.

In the given question we have to find the dimensions of the rectangle with maximum area.

Given Semicircle Radius is 5.

As we know that standard equation of circle is [tex]x^2+y^2=a^2[/tex]

a=5, so the equation is [tex]x^2+y^2=(5)^2[/tex]

[tex]x^2+y^2=25[/tex]

Therefore, Half circle y=[tex]\sqrt{25-x^2}[/tex]

Area of Rectangle(A) =xy

Because Half of the rectangle is lies in first quadrant and half lies in second quadrant

Therefore,

Area of Rectangle(A) = 2xy

Now putting the value of y

Area(A) = 2x[tex]\sqrt{25-x^2}[/tex]

Here we need to maximize the area of Rectangle, so find derivative and set equal to zero.

A'= [tex]\frac{d}{dx}(2x\sqrt{25-x^2})[/tex]

A'= 2[tex][x\frac{d}{dx}\sqrt{25-x^2}+\sqrt{25-x^2}\frac{d}{dx}x][/tex]

A'= 2[tex][x\cdot\frac{-x}{\sqrt{25-x^2}}+\sqrt{25-x^2}\cdot1][/tex]

A'= 2[tex][\frac{-x^2}{\sqrt{25-x^2}}+\sqrt{25-x^2}][/tex]

A'= 2[tex](\frac{-x^2+25-x^2}{\sqrt{25-x^2}})[/tex]

A'= 2[tex](\frac{25-2x^2}{\sqrt{25-x^2}})[/tex]

For critical Number A' = 0

2[tex](\frac{25-2x^2}{\sqrt{25-x^2}})[/tex] = 0

25-2x^2 = 0

2x^2=25

x^2=25/2

x=±√25/2

x=±5/√2

Therefore,

Base of the Rectangle = 2x

Base of the Rectangle = 2×5/√2

Base of the Rectangle = 5√2

and

height of rectangle = [tex]\sqrt{25-x^2}[/tex]

height of rectangle = [tex]\sqrt{25-(5/\sqrt{2})^2}[/tex]

height of rectangle = [tex]\sqrt{25-(25/2)}[/tex]

height of rectangle = √(50-25)/2

height of rectangle = √25/2

height of rectangle = 5/√2

Hence, the dimensions of the rectangle with maximum area are 5√2 and 5/√2.

To learn more about area of rectangle link is here

brainly.com/question/20693059

#SPJ4