A hemispherical dome of radius 50 feet is to be given 7 coats of paint, each of which is 1/100 inch thick. Use linear approximation to estimate the volume of paint needed for the job.
( Hint: Approximate the change in the volume of a hemisphere when the radius increases from 50 feet to 50 feet 7/100 inches. Don't forget to make sure this increased radius is in terms of feet. )
It will take approximately ______ cubic feet of paint to apply all 7 coats of pain.

Respuesta :

Answer:

[tex]91.67 ft^3[/tex]

Step-by-step explanation:

We are given that radius of  hemispherical dome=50 feet

Number of coats of paint=7

Thickness of each coat of paint=[tex]\frac{1}{100} in[/tex]

We have to find the volume of paint by using linear approximation

Volume of hemisphere=[tex]\frac{2}{3}\pi r^3[/tex]

Differentiate w.r.t r

Then, we get [tex]\frac{dv}{dr}=2\pi r^2[/tex]

[tex]\delta r=\frac{1}{100\times 12}\times 7=\frac{7}{1200} feet [/tex]

By approximation

[tex]\delta V=\frac{dV}{dr}\delta r[/tex]

Substitute the values then we get

[tex]\delta V=2\pi r^2\cdot \frac{7}{1200}[/tex]

[tex]\delta V=2\times \frac{22}{7}\times (50)^2\times \frac{7}{1200}=91.67 ft^3[/tex]

The volume of paint needed for the job using linear approximation is; δV = 91.67 ft³

How to find change in volume of hemisphere?

We are given;

Radius of  hemispherical dome; r = 50 feet

Number of coats of paint; n = 7

Thickness of each coat of paint; t = 1/100 inch = 1/1200 ft

Volume of hemisphere is;

V = ²/₃πr³

Differentiating with respect to r gives;

dV/dr = 2πr²

δr = 1/1200 ft * 7

δr = 7/1200 ft

By linear approximation;

δV = dv/dr * δr

δV = 2π(50)² * 7/1200

δV = 91.67 ft³

Read more about hemisphere volume at; https://brainly.com/question/23979348