Calculus 1 : Rate

Study concepts, example questions & explanations for Calculus 1

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Example Questions

Example Question #481 : Rate

Find the slope of  the following function at \(\displaystyle x=1\).

\(\displaystyle f(x)= (e^x)^2\)

Possible Answers:

\(\displaystyle 3.21\)

\(\displaystyle 14.8\)

\(\displaystyle 23.6\)

\(\displaystyle .03\)

\(\displaystyle 32.8\)

Correct answer:

\(\displaystyle 14.8\)

Explanation:

In order to find the slope of a function, you must first differentiate that function.

In this case, the derivative of the given function is: \(\displaystyle f'(x)= 2e^{2x}\)

Then, plug \(\displaystyle x=1\) into the function to get the slope: \(\displaystyle f'(1)= 2e^{2(1)}\)

Therefore, the slope is: \(\displaystyle 14.8\)

Example Question #482 : Rate

Find the slope of  the following function at \(\displaystyle x=3\).

\(\displaystyle f(x)= \cos(x^3)\)

Possible Answers:

\(\displaystyle 25.8\)

\(\displaystyle 27.8\)

\(\displaystyle 29.8\)

\(\displaystyle -27.8\)

\(\displaystyle -25.8\)

Correct answer:

\(\displaystyle -25.8\)

Explanation:

In order to find the slope of a function, you must first differentiate that function.

In this case, the derivative of the given function is: \(\displaystyle f'(x)= -\sin(x^3) 3x^2\)

Then, plug \(\displaystyle x=3\) into the function to get the slope: \(\displaystyle f'(3)= -\sin((3)^3) 3(3)^2\)

Therefore, the slope is: \(\displaystyle -25.8\)

Example Question #483 : Rate

Find the slope of  the following function at \(\displaystyle x=0\).

\(\displaystyle f(x)= 5x^3 + (2x - ln(x))^2\)

Possible Answers:

\(\displaystyle 2\)

\(\displaystyle -1\)

\(\displaystyle 0\)

\(\displaystyle 1\)

\(\displaystyle undefined\)

Correct answer:

\(\displaystyle undefined\)

Explanation:

In order to find the slope of a function, you must first differentiate that function.

In this case, the derivative of the given function is: \(\displaystyle f'(x)= 15x^2 + 2(2x - ln(x))(2-\frac{1}{x})\)

Then, plug \(\displaystyle x=0\) into the function to get the slope: \(\displaystyle f'(0)= 15(0)^2 + 2(2(0) - ln(0))(2-\frac{1}{(0)})\)

Therefore, the slope is: \(\displaystyle undefined\)

Example Question #484 : Rate

Find the slope of  the following function at \(\displaystyle x=-1\).

\(\displaystyle f(x)= ln(2x) + \cos (\sin x)\)

Possible Answers:

\(\displaystyle -0.6\)

\(\displaystyle 0.8\)

\(\displaystyle .33\)

\(\displaystyle -1.5\)

\(\displaystyle 1.2\)

Correct answer:

\(\displaystyle -0.6\)

Explanation:

In order to find the slope of a function, you must first differentiate that function.

In this case, the derivative of the given function is: \(\displaystyle f'(x)= \frac{1}{x} -\sin (\sin x) (\cos x)\)

Then, plug \(\displaystyle x=-1\) into the function to get the slope: \(\displaystyle f'(-1)= \frac{1}{(-1)} -\sin (\sin (-1)) (\cos (-1))\)

Therefore, the slope is: \(\displaystyle -0.6\)

 

Example Question #3302 : 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 diagonal when its sides have length \(\displaystyle 13\sqrt{3}\)?

Possible Answers:

\(\displaystyle 507\sqrt{3}\)

\(\displaystyle 351\sqrt{3}\)

\(\displaystyle 13\sqrt{3}\)

\(\displaystyle 169\sqrt{3}\)

\(\displaystyle 3\sqrt5\)

Correct answer:

\(\displaystyle 507\sqrt{3}\)

Explanation:

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

\(\displaystyle V=s^3\)

\(\displaystyle d=s\sqrt{3}\)

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

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

\(\displaystyle \frac{dd}{dt}=\sqrt{3}\frac{ds}{dt}\)

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

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

\(\displaystyle \phi=s^2\sqrt{3}\)

\(\displaystyle \phi =(13\sqrt{3})^2\sqrt{3}=507\sqrt{3}\)

Example Question #2281 : Functions

What is the slope at \(\displaystyle x=3\) given the following function: \(\displaystyle f(x) = 12x^{\frac{1}{2}} + (6x^2 - 5x +2)^2\)

Possible Answers:

\(\displaystyle 3,545.5\)

\(\displaystyle 1,545.5\)

\(\displaystyle 2,545.5\)

\(\displaystyle 545.5\)

\(\displaystyle 5,545.5\)

Correct answer:

\(\displaystyle 2,545.5\)

Explanation:

In order to find the slope of a function, you must find its derivative. 

In this case, we must find the derivative of the following: \(\displaystyle f(x) = 12x^{\frac{1}{2}} + (6x^2 - 5x +2)^2\)

That is done by doing the following: \(\displaystyle f'(x) = (\frac{1}{2})12x^{(\frac{1}{2}-1)} + (2)(6x^2 - 5x +2)^{(2-1)}((2)6x^{(2-1)}- (1)5x^{(1-1)}+0 )\)

So, the derivative is: \(\displaystyle f'(x) = 6x^{-\frac{1}{2}} + 2(6x^2 - 5x +2) (12x- 5 )\)

Then, you plug \(\displaystyle x=3\) into the derivative: \(\displaystyle f'(3) = 6(3)^{-\frac{1}{2}} + 2(6(3)^2 - 5(3) +2) (12(3)- 5 )\)

Therefore, the answer is: \(\displaystyle 2,545.5\)

 

Example Question #482 : Rate

What is the slope at \(\displaystyle x=0\) given the following function: \(\displaystyle f(x) = \sin(x^2+2x-3)\)

Possible Answers:

\(\displaystyle 2.98\)

\(\displaystyle -3\)

\(\displaystyle -1.98\)

\(\displaystyle 1\)

\(\displaystyle 3.2\)

Correct answer:

\(\displaystyle -1.98\)

Explanation:

In order to find the slope of a function, you must find its derivative. 

In this case, we must find the derivative of the following: \(\displaystyle f(x) = \sin(x^2+2x-3)\)

That is done by doing the following: \(\displaystyle f'(x) = \cos (x^2+2x-3) ((2)x^{(2-1)} + (1)2x^{(1-1)} + 0)\)

Therefore, the derivative is: \(\displaystyle f'(x) = \cos (x^2+2x-3) (2x + 2)\)

Then, you plug \(\displaystyle x=0\) into the derivative: \(\displaystyle f'(0) = \cos ((0)^2+2(0)-3) (2(0) + 2)\)

Therefore, the answer is: \(\displaystyle -1.98\)

 

Example Question #2281 : Functions

What is the slope at \(\displaystyle x=0\) given the following function: \(\displaystyle f(x) = ln(2x^3 + e^x)\)

Possible Answers:

\(\displaystyle 2\)

\(\displaystyle -4\)

\(\displaystyle 1\)

\(\displaystyle 3\)

\(\displaystyle 0\)

Correct answer:

\(\displaystyle 1\)

Explanation:

In order to find the slope of a function, you must find its derivative. 

In this case, we must find the derivative of the following: \(\displaystyle f(x) = ln(2x^3 + e^x)\)

That is done by doing the following: \(\displaystyle f'(x) = \frac{1}{2x^3+e^x} ((3)2x^{(3-1)} + e^x)\)

Therefore, the derivative is: \(\displaystyle f'(x) = \frac{6x^2+e^x}{2x^3 + e^x}\)

Then, you plug \(\displaystyle x=0\) into the derivative: \(\displaystyle f'(0) = \frac{6(0)^2+e^(0)}{2(0)^3 + e^(0)}\)

Therefore, the answer is: \(\displaystyle 1\)

Example Question #3311 : Calculus

What is the slope at \(\displaystyle x=1\) given the following function: \(\displaystyle f(x) = e^{4x}\)

Possible Answers:

\(\displaystyle 234.9\)

\(\displaystyle 345.8\)

\(\displaystyle 134.5\)

\(\displaystyle 218.4\)

\(\displaystyle 20\)

Correct answer:

\(\displaystyle 218.4\)

Explanation:

In order to find the slope of a function, you must find its derivative. 

In this case, we must find the derivative of the following: \(\displaystyle f(x) = e^{4x}\)

That is done by doing the following: \(\displaystyle f'(x) = e^{4x} ((1)4x^{(1-1)})\)

Therefore, the derivative is: \(\displaystyle f'(x) = 4e^{4x}\)

Then, you plug \(\displaystyle x=1\) into the derivative: \(\displaystyle f'(1) = 4e^{4(1)}\)

Therefore, the answer is: \(\displaystyle 218.4\)

Example Question #401 : Rate Of Change

What is the slope at \(\displaystyle x=1\) given the following function: \(\displaystyle f(x) = \sin (ln(2x))\)

Possible Answers:

\(\displaystyle 2.85\)

\(\displaystyle .093\)

\(\displaystyle 0.77\)

\(\displaystyle 0.67\)

\(\displaystyle -0.87\)

Correct answer:

\(\displaystyle 0.77\)

Explanation:

In order to find the slope of a function, you must find its derivative. 

In this case, we must find the derivative of the following: \(\displaystyle f(x) = \sin (ln(2x))\)

That is done by doing the following: \(\displaystyle f'(x) = \cos (ln(2x)) (\frac{1}{2x}) ((1)2x^{(1-1)})\)

Therefore, the derivative is: \(\displaystyle f'(x) = \frac{\cos (ln(2x))}{x}\)

Then, you plug \(\displaystyle x=1\) into the derivative: \(\displaystyle f'(1) = \frac{\cos (ln(2(1)))}{(1)}\)

Therefore, the answer is: \(\displaystyle 0.77\)

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