Calculus AB : Calculus AB

Study concepts, example questions & explanations for Calculus AB

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Example Questions

Example Question #2 : Connect Position, Velocity, And Acceleration

Given a particle with an acceleration at time \displaystyle t to be \displaystyle a(t)=4 . With initial conditions \displaystyle v(0)=4 and \displaystyle p(0)=-4 where \displaystyle v(t) is the velocity at time \displaystyle t, and \displaystyle p(t) is position of the particle at time \displaystyle t.

Find the position at time \displaystyle t.

Possible Answers:

\displaystyle p(t)=2t^2+4t-4

\displaystyle p(t)=2t^2+t-4

\displaystyle p(t)=2t^2

\displaystyle p(t)=t^2+t+4

\displaystyle p(t)=2t^2-4t

Correct answer:

\displaystyle p(t)=2t^2+4t-4

Explanation:

We first must establish the following relationship

\displaystyle p''(t)=a(t) and \displaystyle p'(t)=v(t)

We now may note that 

\displaystyle \int a(t)dt=v(t)+C or \displaystyle \int4dt=4t+C=v(t)

Since \displaystyle v(t)=3t+C

We must plug in our initial condition \displaystyle v(0)=4

Therefore our new velocity equation is \displaystyle v(t)=4t+4

We now may similarly integrate the velocity equation to find position.

\displaystyle \int(4t+4)dt=2t^2+4t+C

Plugging in our second initial condition \displaystyle p(0)=-4

We find our final equation to be:

\displaystyle p(t)=2t^2+4t-4

Example Question #1 : Connect Position, Velocity, And Acceleration

Find the velocity function given the following information:

The acceleration function is  \displaystyle a(t)=3t+\cos(t);

\displaystyle v(0)=3

Possible Answers:

\displaystyle \frac{3t^2}{2}+\sin(t)+C

\displaystyle \frac{3t^2}{2}-\sin(t)+3

\displaystyle \frac{3t^2}{2}+\sin(t)+3

\displaystyle \frac{t^2}{2}+\sin(t)+3

Correct answer:

\displaystyle \frac{3t^2}{2}+\sin(t)+3

Explanation:

To find the velocity function, we integrate the acceleration function (the acceleration is the antiderivative of the velocity):

\displaystyle v(t)=\int a(t)dt=\int [3t +\cos(t)]dt =\frac{ 3t^2}{2}+\sin(t)+C

The rules of integration used were

\displaystyle \int x^n dx = \frac{x^{n+1}}{n+1}+C\displaystyle \int \cos(t)dt= \sin(t)+C

To solve for the integration constant, we plug in the given initial condition:

\displaystyle v(0)=3=0+0+C

\displaystyle 3=C

Our final answer is

\displaystyle v(t)=\frac{3t^2}{2}+\sin(t)+3

Example Question #3 : Connect Position, Velocity, And Acceleration

What is the position function if the initial position is 0 and the velocity function is given by \displaystyle v(t)=10t+1?

Possible Answers:

\displaystyle 5t^2+1

\displaystyle \frac{5t^2}{2}+t

\displaystyle 0

\displaystyle 5t^2+t

Correct answer:

\displaystyle 5t^2+t

Explanation:

To find the position function, we must integrate the velocity function, as velocity is the antiderivative of position:

\displaystyle s(t)=\int v(t) dt = \int (10t+1)dt = 5t^2+t+C

The following rule of integration was used:

\displaystyle \int x^n dx = \frac{x^{n+1}}{n+1}+C

Finally, we use the initial condition to solve for the integration constant:

\displaystyle s(0)=0=0+0+C

\displaystyle C=0

Our final answer is

\displaystyle s(t)=5t^2+t

Example Question #4 : Connect Position, Velocity, And Acceleration

A particle at the origin has an initial velocity of \displaystyle 32 \displaystyle m/s. If its acceleration is given by \displaystyle a = -24t^2 + 6t - 8, find the position of the particle after 1 second.

Possible Answers:

\displaystyle 32m

\displaystyle 18m

\displaystyle 27m

\displaystyle 29m

\displaystyle 24m

Correct answer:

\displaystyle 27m

Explanation:

In this problem, letting \displaystyle s(t) denote the position of the particle and \displaystyle v(t) denote the velocity, we know that \displaystyle s''(t) = v'(t) = a(t). Integrating and working backwards we have,

\displaystyle v(t) = \int a(t)dt = \int (-24t^2 + 6t - 8)dt = -8t^3 + 3t^2 -8t + C

Plugging in our initial condition, \displaystyle v(0) = 32, we see immediately that \displaystyle C = 32.

Repeating the process again for \displaystyle s(t), we find that 

 \displaystyle s(t) = \int v(t)dt = \int (-8t^3 + 3t^2 -8t +32)dt = -2t^4 + t^3 - 4t^2 + 32t + C

Plugging in our initial condition, \displaystyle s(0) = 0 (we started at the origin) we see that \displaystyle C = 0. This gives us a final equation

\displaystyle s(t) = -2t^4 + t^3 - 4t^2 + 32t. The problem asks for \displaystyle s(1) which is simply \displaystyle s(t) = -2(1)^4 + (1)^3 - 4(1)^2 + 32(1) = -4 + 1 - 4 + 32 = 27

Example Question #2 : Connect Position, Velocity, And Acceleration

Find the integral which satisfies the specific conditions of \displaystyle (\frac{\pi}{2}, 4)

\displaystyle \int4sin(t)-12cos(t)+3t^2dt

Possible Answers:

\displaystyle y=-4cos(t)-12sin(t)+t^3+12.12

\displaystyle y=4cos(t)+12sin(t)+t^3

\displaystyle y=-16tan(t)+t^3+12.12

\displaystyle y=-4tcos(t)-12tsin(t)+t^3

Correct answer:

\displaystyle y=-4cos(t)-12sin(t)+t^3+12.12

Explanation:

Find the integral which satisfies the specific conditions of \displaystyle (\frac{\pi}{2}, 4)

\displaystyle \int4sin(t)-12cos(t)+3t^2dt

To do this problem, we need to recall that integrals are also called anti-derivatives. This means that we can calculate integrals by reversing our integration rules.

Furthermore, to find the specific answer using initial conditions, we need to find our "c" at the end.

Thus, we can have the following rules.

\displaystyle \int sin(t)dt = -cos(t)+c

\displaystyle \int cos(t)dt = sin(t)+c

\displaystyle \int t^ndt=\frac{t^{n+1}}{n+1}+c

Using these rules, we can find our answer:

\displaystyle \int4sin(t)-12cos(t)+3t^2dt 

Will become:

\displaystyle -4cos(t)-12sin(t)+\frac{3t^3}{3}+c=-4cos(t)-12sin(t)+t^3+c

And so our anti-derivative is:

\displaystyle -4cos(t)-12sin(t)+t^3+c

Now, let's find c. First set our above expression equal to y

\displaystyle y= -4cos(t)-12sin(t)+t^3+c

Next, plug in   for y and t. Then solve for c

\displaystyle 4= -4cos(\frac{\pi}{2})-12sin(\frac{\pi}{2})+(\frac{\pi}{2})^3+c

Looks a bit messy, but we can clean it up to get:

\displaystyle 4= 0-12+3.88+c\rightarrow 4=-8.12+c\rightarrow c=12.12

Now, to solve, simply replace c with 12.12

\displaystyle y=-4cos(t)-12sin(t)+t^3+12.12

Example Question #1 : Find Average Value

Which of the following theorems is related to finding the Average Value of a Function?

Possible Answers:

Mean Value Theorem for Integrals

Fundamental Theorem of Calculus

Extreme Value Theorem

Intermediate Value Theorem

Correct answer:

Mean Value Theorem for Integrals

Explanation:

The following equation is used for finding the Average Value of a Function:  \displaystyle f_{avg}=\frac{1}{b-a} \int_{a}^{b} f(x) dx. A rearrangement of this equation could be multiplying \displaystyle (b-a) to both sides. Making this rearrangement, and substituting \displaystyle f_{avg}=f(c) with \displaystyle a< c< b, results in the following: \displaystyle \int_{a}^{b}f(x) dx=f(c)(b-a). Assuming \displaystyle f(x) is continuous, this is the correct equation for the Mean Value Theorem for Integrals.

Example Question #2 : Find Average Value

Find the average value of the function \displaystyle f(x)=2x^7+5x^2+4 over the interval \displaystyle [1,3]. Round to the nearest hundredth.

Possible Answers:

\displaystyle 1691.33

\displaystyle 103.45

\displaystyle 846.50

\displaystyle 845.67

Correct answer:

\displaystyle 845.67

Explanation:

When finding the average value of a function, it is useful to keep the following formula in mind: \displaystyle f_{avg}=\frac{1}{b-a}\int_{a}^{b}f(x) dx. This equation is very helpful because it provides a simple way to determine the average value by substituting in values of the bounds and the function itself:

\displaystyle f_{avg}=\frac{1}{3-1}\int_{1}^{3}2x^7+5x^2+4 dx=(12)[\frac{1}{4}x^8+\frac{5}{3}x^3+4x] |_1^3\displaystyle =(\frac{1}{2})(\frac{6561}{4}+45+12-1\frac{}{4}-\frac{5}{3}-4)=845.67

Example Question #671 : Calculus Ab

Find the average value of the function \displaystyle f(x)=4e^{2x} over the interval \displaystyle [0,5]

Possible Answers:

\displaystyle \frac{2}{5}(e^{10}-1)

\displaystyle \frac{2}{5}(e^5-1)

\displaystyle e^5

\displaystyle 2e^10

Correct answer:

\displaystyle \frac{2}{5}(e^{10}-1)

Explanation:

When finding the average value of a function, it is useful to keep the following formula in mind: \displaystyle f_{avg}=\frac{1}{b-a}\int_{a}^{b}f(x) dx. This equation is very helpful because it provides a simple way to determine the average value by substituting in values of the bounds and the function itself:

\displaystyle f_{avg}=\frac{1}{5-0}\int_{0}^{5}4e^{2x} dx=(\frac{1}{5})[4e^{2x} * \frac{1}{2}] |_0^5 =\frac{2}{5}e^{2(5)}-\frac{2}{5}e^{2(0)}=\frac{2}{5}(e^{10}-1)

Example Question #681 : Calculus Ab

Find the average value of the function \displaystyle f(t)=4+2cos(2t) over the interval \displaystyle [0,\frac{\pi}{4}].

Possible Answers:

\displaystyle 1+\frac{4}{\pi}

\displaystyle 4-\frac{4}{\pi}

\displaystyle 4+\frac{4}{\pi}

\displaystyle \frac{\pi}{4} + 2

Correct answer:

\displaystyle 4+\frac{4}{\pi}

Explanation:

When finding the average value of a function, it is useful to keep the following formula in mind: \displaystyle f_{avg}=\frac{1}{b-a}\int_{a}^{b}f(x) dx. This equation allows the substitution of the function and interval to solve for the average value. While the function in this problem contains a trigonometric function, the same approach can be applied. Remember that the function is in terms of t, so the definite integral expression should likewise be in terms of \displaystyle t.

\displaystyle f_{avg}=\frac{1}{\frac{\pi}{4}-0}\int_{0}^{\frac{\pi}{4}}4+2cos(2t) dt=(\frac{4}{\pi})[4t+sin(2t)] |_0^{\frac{\pi}{4}}\displaystyle =(\frac{4}{\pi})[\pi +1-0-0]=4+\frac{4}{\pi}

Example Question #3 : Find Average Value

Identify the correct integral expression for the average value of the function\displaystyle f(t)=6-3tsin(t^2) over the interval \displaystyle [0,\pi].

Possible Answers:

\displaystyle \frac{1}{\pi}\int_{0}^{\pi}6-3xsin(x^2) dt

\displaystyle \frac{1}{\pi}\int_{0}^{\pi}6-3tsin(t^2) dt

\displaystyle \int_{0}^{\pi}6-3tsin(t^2) dt

\displaystyle \int_{0}^{\pi}6-3tsin(t^2) dx

Correct answer:

\displaystyle \frac{1}{\pi}\int_{0}^{\pi}6-3tsin(t^2) dt

Explanation:

When finding the average value of a function, it is useful to keep the following formula in mind: \displaystyle f_{avg}=\frac{1}{b-a}\int_{a}^{b}f(x) dx. This equation allows the substitution of the function and interval to solve for the average value. While the function in this problem contains a trigonometric function, the same approach can be applied. Remember that the function is in terms of \displaystyle t, so the definite integral expression should likewise be in terms of \displaystyle t.

\displaystyle f_{avg}=\frac{1}{\pi-0}\int_{0}^{\pi}6-(3t)sin(t^2) dt =\frac{1}{\pi}\int_{0}^{\pi}6-3tsin(t^2) dt

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