Respuesta :
Answer:
Length of the sides of the base (x) = 7.606 ft
Height (h) = 3.802 ft
The minimum surface area is 173.55 ft²
Step-by-step explanation:
Surface area is given by:
[tex]S(x) = x^2+\frac{880}{x}[/tex]
The value of x for which the derivate of the surface area function is zero, is the length of the sides of the base that minimizes surface area:
[tex]S(x) = x^2+\frac{880}{x} \\\frac{dS(x)}{dx}=0=2x-\frac{880}{x^2}\\x^3=440\\x=7.606\ ft[/tex]
The height of the box is given by:
[tex]V=hx^2\\220 =h*7.606^2\\h=3.802\ ft[/tex]
The dimensions of the box with minimum surface area are:
Length of the sides of the base (x) = 7.606 ft
Height (h) = 3.802 ft
The absolute minimum is:
[tex]S(x) = 7.606^2+\frac{880}{7.606}\\S_{min}=173.55\ ft^2[/tex]
The minimum surface area is 173.55 ft²
Answer:
The absolute minimum of the surface area[tex]=173.55$ ft^2[/tex]
At the minimum surface area,
- Base length=7.61 feet
- Height of 3.8 feet.
Step-by-step explanation:
Volume of the box =220 cubic feet.
[tex]\text{Surface Area, } S(x)=x^2+\dfrac{880}{x}[/tex]
To find the absolute minimum of the surface area function on the interval [tex](0,\infty)[/tex], we take the derivative of S(x) and solve for its critical points.
[tex]S(x)=\dfrac{x^3+880}{x}\\S'(x)=\dfrac{2x^3-880}{x^2}\\$Setting the derivative equal to 0\\S'(x)=\dfrac{2x^3-880}{x^2}=0\\2x^3-880=0\\2x^3=880\\$Divide both sides by 2\\x^3=440[/tex]
Take the cube root of both sides
[tex]x=\sqrt[3]{440}\\ x=7.61$ ft[/tex]
Therefore, the absolute minimum of the surface area function on the interval [tex](0,\infty)[/tex], is:
[tex]S(x)=\dfrac{7.61^3+880}{7.61}\\\\=173.55$ ft^2[/tex]
Since the volume of the box =220 cubic feet
[tex]V=x^2h\\220=7.61^2 \times h\\h=220 \div 7.61^2\\h=3.80 ft[/tex]
The dimensions of the box with the minimum surface area are base length of 7.61 feet and height of 3.8 feet.
