Assume that the radius rr of a sphere is expanding at a rate of 19 in./min.19 in./min. The volume of a sphere is V=43πr3V=43πr3. Determine the rate at which the volume is changing with respect to time when t=5 min.t=5 min. assuming that r=4r=4 at t=0t=0. The volume is changing at a rate of

Respuesta :

Answer:

[tex]744876\pi in^3/min[/tex].

Step-by-step explanation:

We are given that

[tex]\frac{dr}{dt}=19 in/min[/tex]

Volume of sphere=[tex]\frac{4}{3}\pi r^3[/tex]

[tex]r=4 at t=0[/tex]

[tex]dr=19 dt[/tex]

Integrating on both sides then  we get

[tex]r=19 t+C[/tex]

Substitute r=4 and t=0

[tex]4=C[/tex]

[tex]r=19t+4[/tex]

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

[tex]\frac{dV}{dt}=4\pi (19t+4)^2(19)[/tex]

Substitute t=5

[tex]\frac{dV}{dt}=4\pi (19(5)+4)^2(19)[/tex]

[tex]\frac{dV}{dt}=4 \pi (99)^2 (19)=744876\pi in^3/min [/tex]

Hence, the volume is changing at the rate of [tex]744876\pi in^3/min[/tex].

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