The volume Vequalsfour thirds pi r cubed of a spherical balloon changes with the radius. a. At what rate ​(ftcubed​/ft​) does the volume change with respect to the radius when r equals 2 ft question mark b. Using the rate from part a​, by approximately how much does the volume increase when the radius changes from 2 to 2.4 ft question mark

Respuesta :

Answer:

a) [tex]\frac{dv}{dr} = 16\pi cubic ft /ft[/tex]

b) Approximate error of the volume increase when the radius changes from 2 to 2.4 ft = 0.6 that is

[tex]\frac{dv}{v} =0.6 cubic ft /ft[/tex]

Step-by-step explanation:

Explanation:-

a) Given Volume of spherical balloon

[tex]V = \frac{4\pi r^{3} }{3}[/tex]         …(i)

Differentiating with respective to the radius 'r'

[tex]\frac{dv}{dt} = \frac{4\pi 3r^{2} }{3}[/tex]

[tex]\frac{dv}{dt} = 4 \pi r^{2}[/tex]

At r=2

[tex](\frac{dv}{dr})r_{=2} =4\pi (4)=16\pi cubeft/ft[/tex]

b) Step(1):-

Given Volume of spherical balloon

[tex]V = \frac{4\pi r^{3} }{3}[/tex]

 [tex]logV = log(\frac{4\pi r^{3} }{3})[/tex]

we property of logarithmic log(ab) = log a +log b

taking logarithmic on both sides , we get

[tex]logv = log(\frac{4\pi }{3} )+log(r^{3})[/tex] …(ii)

Step2:-

we will use   [tex]\frac{d(logx)}{dx} = \frac{1}{x}[/tex]

[tex]\frac{1}{v}[/tex] δ v = 0 + [tex]3 \frac{1}{r}[/tex] δ r

Given data  radius changes from 2 to 2.4 ft

r+ δ r = 2.4 =2+0.4

here r =2 and δ r =0.4

Now [tex]\frac{1}{v}[/tex] δ v =  [tex]3 X \frac{1}{2} X 0.4[/tex]

[tex]\frac{1}{v}[/tex] δ v = 0.6

Approximate error in Volume = 0.6 cubic/ft

Approximate error of the volume increase when the radius changes from 2 to 2.4 ft = 0.6 that is

[tex]\frac{dv}{v} =0.6 cubic ft /ft[/tex]