Calculus 1 : How to find rate of change

Study concepts, example questions & explanations for Calculus 1

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Example Questions

Example Question #631 : Rate Of Change

A cube is diminishing in size. What is the ratio of the rate of loss of the cube's volume to the rate of loss of its surface area when its sides have length \displaystyle \frac{92}{95}?

Possible Answers:

\displaystyle \frac{46}{19}

\displaystyle \frac{46}{95}

\displaystyle \frac{23}{95}

\displaystyle \frac{23}{19}

\displaystyle \frac{92}{19}

Correct answer:

\displaystyle \frac{23}{95}

Explanation:

Begin by writing the equations for a cube's dimensions. Namely its volume and surface area in terms of the length of its sides:

\displaystyle V=s^3

\displaystyle A=6s^2

The rates of change of these can be found by taking the derivative of each side of the equations with respect to time:

\displaystyle \frac{dV}{dt}=3s^2\frac{ds}{dt}

\displaystyle \frac{dA}{dt}=12s\frac{ds}{dt}

Now, knowing the length of the sides, simply divide to find the ratio between the rate of change of the volume and surface area:

\displaystyle 3s^2\frac{ds}{dt}=(\phi)12s\frac{ds}{dt}

\displaystyle \phi=\frac{s}{4}

\displaystyle \phi =\frac{(\frac{92}{95})}{4}=\frac{23}{95}

Example Question #3541 : Calculus

A cube is diminishing in size. What is the ratio of the rate of loss of the cube's volume to the rate of loss of its surface area when its sides have length \displaystyle \frac{32}{41}?

Possible Answers:

\displaystyle \frac{8}{41}

\displaystyle \frac{64}{41}

\displaystyle \frac{16}{41}

\displaystyle \frac{32}{41}

\displaystyle \frac{4}{41}

Correct answer:

\displaystyle \frac{8}{41}

Explanation:

Begin by writing the equations for a cube's dimensions. Namely its volume and surface area in terms of the length of its sides:

\displaystyle V=s^3

\displaystyle A=6s^2

The rates of change of these can be found by taking the derivative of each side of the equations with respect to time:

\displaystyle \frac{dV}{dt}=3s^2\frac{ds}{dt}

\displaystyle \frac{dA}{dt}=12s\frac{ds}{dt}

Now, knowing the length of the sides, simply divide to find the ratio between the rate of change of the volume and surface area:

\displaystyle 3s^2\frac{ds}{dt}=(\phi)12s\frac{ds}{dt}

\displaystyle \phi=\frac{s}{4}

\displaystyle \phi =\frac{(\frac{32}{41})}{4}=\frac{8}{41}

Example Question #3542 : Calculus

A cube is diminishing in size. What is the ratio of the rate of loss of the cube's volume to the rate of loss of its surface area when its sides have length \displaystyle \frac{79}{80}?

Possible Answers:

\displaystyle \frac{79}{20}

\displaystyle \frac{79}{320}

\displaystyle \frac{79}{5}

\displaystyle \frac{79}{160}

\displaystyle \frac{316}{5}

Correct answer:

\displaystyle \frac{79}{320}

Explanation:

Begin by writing the equations for a cube's dimensions. Namely its volume and surface area in terms of the length of its sides:

\displaystyle V=s^3

\displaystyle A=6s^2

The rates of change of these can be found by taking the derivative of each side of the equations with respect to time:

\displaystyle \frac{dV}{dt}=3s^2\frac{ds}{dt}

\displaystyle \frac{dA}{dt}=12s\frac{ds}{dt}

Now, knowing the length of the sides, simply divide to find the ratio between the rate of change of the volume and surface area:

\displaystyle 3s^2\frac{ds}{dt}=(\phi)12s\frac{ds}{dt}

\displaystyle \phi=\frac{s}{4}

\displaystyle \phi =\frac{(\frac{79}{80})}{4}=\frac{79}{320}

Example Question #3543 : Calculus

A cube is growing in size. What is the ratio of the rate of growth of the cube's volume to the rate of growth of the area of a single face when its sides have length 93?

Possible Answers:

\displaystyle \frac{279}{5}

\displaystyle \frac{31}{2}

\displaystyle \frac{31}{5}

\displaystyle \frac{93}{2}

\displaystyle \frac{279}{2}

Correct answer:

\displaystyle \frac{279}{2}

Explanation:

Begin by writing the equations for a cube's dimensions. Namely its volume and the area of a face in terms of the length of its sides:

\displaystyle V=s^3

\displaystyle a=s^2

The rates of change of these can be found by taking the derivative of each side of the equations with respect to time:

\displaystyle \frac{dV}{dt}=3s^2\frac{ds}{dt}

\displaystyle \frac{dA}{dt}=2s\frac{ds}{dt}

Now, knowing the length of the sides, simply divide to find the ratio between the rate of change of the volume and surface area:

\displaystyle 3s^2\frac{ds}{dt}=(\phi)2s\frac{ds}{dt}

\displaystyle \phi=\frac{3s}{2}

\displaystyle \phi =\frac{3(93)}{2}=\frac{279}{2}

Example Question #631 : Rate Of Change

A cube is growing in size. What is the ratio of the rate of growth of the cube's volume to the rate of growth of the area of a single face when its sides have length 166?

Possible Answers:

\displaystyle 83

\displaystyle 249

\displaystyle 41.5

\displaystyle 166

\displaystyle 332

Correct answer:

\displaystyle 249

Explanation:

Begin by writing the equations for a cube's dimensions. Namely its volume and the area of a face in terms of the length of its sides:

\displaystyle V=s^3

\displaystyle a=s^2

The rates of change of these can be found by taking the derivative of each side of the equations with respect to time:

\displaystyle \frac{dV}{dt}=3s^2\frac{ds}{dt}

\displaystyle \frac{dA}{dt}=2s\frac{ds}{dt}

Now, knowing the length of the sides, simply divide to find the ratio between the rate of change of the volume and surface area:

\displaystyle 3s^2\frac{ds}{dt}=(\phi)2s\frac{ds}{dt}

\displaystyle \phi=\frac{3s}{2}

\displaystyle \phi =\frac{3(166)}{2}=249

Example Question #2519 : Functions

A cube is growing in size. What is the ratio of the rate of growth of the cube's volume to the rate of growth of the area of a single face when its sides have length 404?

Possible Answers:

\displaystyle 202

\displaystyle 404

\displaystyle 101

\displaystyle 606

\displaystyle 1212

Correct answer:

\displaystyle 606

Explanation:

Begin by writing the equations for a cube's dimensions. Namely its volume and the area of a face in terms of the length of its sides:

\displaystyle V=s^3

\displaystyle a=s^2

The rates of change of these can be found by taking the derivative of each side of the equations with respect to time:

\displaystyle \frac{dV}{dt}=3s^2\frac{ds}{dt}

\displaystyle \frac{dA}{dt}=2s\frac{ds}{dt}

Now, knowing the length of the sides, simply divide to find the ratio between the rate of change of the volume and surface area:

\displaystyle 3s^2\frac{ds}{dt}=(\phi)2s\frac{ds}{dt}

\displaystyle \phi=\frac{3s}{2}

\displaystyle \phi =\frac{3(404)}{2}=606

Example Question #631 : Rate Of Change

A cube is growing in size. What is the ratio of the rate of growth of the cube's volume to the rate of growth of the area of a single face when its sides have length 864?

Possible Answers:

\displaystyle 72

\displaystyle 432

\displaystyle 216

\displaystyle 1296

\displaystyle 5184

Correct answer:

\displaystyle 1296

Explanation:

Begin by writing the equations for a cube's dimensions. Namely its volume and the area of a face in terms of the length of its sides:

\displaystyle V=s^3

\displaystyle a=s^2

The rates of change of these can be found by taking the derivative of each side of the equations with respect to time:

\displaystyle \frac{dV}{dt}=3s^2\frac{ds}{dt}

\displaystyle \frac{dA}{dt}=2s\frac{ds}{dt}

Now, knowing the length of the sides, simply divide to find the ratio between the rate of change of the volume and surface area:

\displaystyle 3s^2\frac{ds}{dt}=(\phi)2s\frac{ds}{dt}

\displaystyle \phi=\frac{3s}{2}

\displaystyle \phi =\frac{3(864)}{2}=1296

Example Question #721 : Rate

A cube is growing in size. What is the ratio of the rate of growth of the cube's volume to the rate of growth of the area of a single face when its sides have length 428?

Possible Answers:

\displaystyle 642

\displaystyle 535

\displaystyle 214

\displaystyle 321

\displaystyle 107

Correct answer:

\displaystyle 642

Explanation:

Begin by writing the equations for a cube's dimensions. Namely its volume and the area of a face in terms of the length of its sides:

\displaystyle V=s^3

\displaystyle a=s^2

The rates of change of these can be found by taking the derivative of each side of the equations with respect to time:

\displaystyle \frac{dV}{dt}=3s^2\frac{ds}{dt}

\displaystyle \frac{dA}{dt}=2s\frac{ds}{dt}

Now, knowing the length of the sides, simply divide to find the ratio between the rate of change of the volume and surface area:

\displaystyle 3s^2\frac{ds}{dt}=(\phi)2s\frac{ds}{dt}

\displaystyle \phi=\frac{3s}{2}

\displaystyle \phi =\frac{3(428)}{2}=642

Example Question #722 : Rate

A cube is growing in size. What is the ratio of the rate of growth of the cube's volume to the rate of growth of the area of a single face when its sides have length 296?

Possible Answers:

\displaystyle 74

\displaystyle 222

\displaystyle 444

\displaystyle 148

\displaystyle 111

Correct answer:

\displaystyle 444

Explanation:

Begin by writing the equations for a cube's dimensions. Namely its volume and the area of a face in terms of the length of its sides:

\displaystyle V=s^3

\displaystyle a=s^2

The rates of change of these can be found by taking the derivative of each side of the equations with respect to time:

\displaystyle \frac{dV}{dt}=3s^2\frac{ds}{dt}

\displaystyle \frac{dA}{dt}=2s\frac{ds}{dt}

Now, knowing the length of the sides, simply divide to find the ratio between the rate of change of the volume and surface area:

\displaystyle 3s^2\frac{ds}{dt}=(\phi)2s\frac{ds}{dt}

\displaystyle \phi=\frac{3s}{2}

\displaystyle \phi =\frac{3(296)}{2}=444

Example Question #721 : Rate

A cube is diminishing in size. What is the ratio of the rate of loss of the cube's volume to the rate of loss of the area of a single face when its sides have length \displaystyle \frac{13}{6}?

Possible Answers:

\displaystyle \frac{13}{2}

\displaystyle \frac{13}{24}

\displaystyle \frac{13}{6}

\displaystyle \frac{13}{12}

\displaystyle \frac{13}{4}

Correct answer:

\displaystyle \frac{13}{4}

Explanation:

Begin by writing the equations for a cube's dimensions. Namely its volume and the area of a face in terms of the length of its sides:

\displaystyle V=s^3

\displaystyle a=s^2

The rates of change of these can be found by taking the derivative of each side of the equations with respect to time:

\displaystyle \frac{dV}{dt}=3s^2\frac{ds}{dt}

\displaystyle \frac{dA}{dt}=2s\frac{ds}{dt}

Now, knowing the length of the sides, simply divide to find the ratio between the rate of change of the volume and surface area:

\displaystyle 3s^2\frac{ds}{dt}=(\phi)2s\frac{ds}{dt}

\displaystyle \phi=\frac{3s}{2}

\displaystyle \phi =\frac{3(\frac{13}{6})}{2}=\frac{13}{4}

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