AP Calculus AB : Applications of antidifferentiation

Study concepts, example questions & explanations for AP Calculus AB

varsity tutors app store varsity tutors android store

Example Questions

←之前 1 3 4

Example Question #1 :Solving Separable Differential Equations And Using Them In Modeling

Find (dy/dx).

sin(xy) = x + cos(y)

Possible Answers:

None of the above

dy/dx = (cos(xy) + sin(y))/(1 – cos(xy))

dy/dx = (1 – cos(xy))/(cos(xy) + sin(y))

dy/dx = (1 – ycos(xy))/(xcos(xy) + sin(y))

dy/dx = (xcos(xy) + sin(y))/(1 – ycos(xy))

有限公司rrect answer:

dy/dx = (1 – ycos(xy))/(xcos(xy) + sin(y))

解释:

The first step of the problem is to differentiate with respect to (dy/dx):

cos(xy)[(x)(dy/dx) + y(1)] = 1 – sin(y)(dy/dx)

*Note: When differentiating cos(xy) remember to use the product rule. (xy' + x'y)

Step 2: Clean the differentiated problem up

cos(xy)(x)(dy/dx) + cos(xy)y = 1 – sin(y)(dy/dx)

cos(xy)(x)(dy/dx) + sin(y)(dy/dx) = 1 – cos(xy)y

Step 3: Solve for (dy/dx)

dy/dx = (1 – ycos(xy))/(xcos(xy) + sin(y))

Example Question #2 :Solving Separable Differential Equations And Using Them In Modeling

Find the equation of the normal line aton the graphy=x^{3}-6x+4.

Possible Answers:

y'=3x^{2}-6

y=\frac{-1}{6}x+2

y=\frac{-1}{6}x+\frac{1}{3}

有限公司rrect answer:

y=\frac{-1}{6}x+\frac{1}{3}

解释:

The answer isy=\frac{-1}{6}x+\frac{1}{3}.

y=x^{3}-6x+4

y'=3x^{2}-6

Now plug in.

y'=3(2)^{2}-6 = 6now we know 6 is the slope for the tangent line. However, we aren't looking for the slope of the tangent line. The slope of the normal line is the negative reciprocal of the tangent's slope; meaning the slope of the normal is\frac{-1}{6}. Now find the equation of the normal line.

y-0=\frac{-1}{6}(x-2)

y=\frac{-1}{6}x+\frac{1}{3}

Example Question #1 :Solving Separable Differential Equations And Using Them In Modeling

f(x) = \frac{x^3}{1-x^2}

What is the derivative of?

Possible Answers:

\frac{x^2(3-5x^2)}{1-x^2}

-x

\frac{-2x^4-3 x^2(1-x^2)}{(1-x^2)^2}

\frac{x^2(3-x^2)}{(1-x^2)^2}

有限公司rrect answer:

\frac{x^2(3-x^2)}{(1-x^2)^2}

解释:

Use the quotient rule.

Example Question #1 :Solving Separable Differential Equations And Using Them In Modeling

Findif

y=\frac{ln(x)}{x^{3}}

Possible Answers:

\frac{ln(x)-1}{x^{4}}

\frac{3}{x^{3}}

\frac{1+3ln(x)}{x^{4}}

y'=\frac{1-3ln(x)}{x^{4}}

\frac{1}{x^{4}}

有限公司rrect answer:

y'=\frac{1-3ln(x)}{x^{4}}

解释:

The answer is

y'=\frac{1-3ln(x)}{x^{4}}

y=\frac{ln(x)}{x^{3}}

y'=\frac{(\frac{1}{x})x^{3}-ln(x)(3x^{3})}{x^{6}}

y'=\frac{x^{2}(1-3ln(x))}{x^{6}}

y'=\frac{1-3ln(x)}{x^{4}}

Example Question #1 :Applications Of Antidifferentiation

Find the derivative:

Possible Answers:

有限公司rrect answer:

解释:

To find the derivative, multiply the exponent by the coefficent in front of the x term and then decrease the exponent by 1:

Example Question #6 :Solving Separable Differential Equations And Using Them In Modeling

Find the solution to the equationy'=yatx=2with initial conditiony(0)=2.

Possible Answers:

2e^2

1

e^2

e

2e

有限公司rrect answer:

2e^2

解释:

First, we need to solve the differential equation ofy'=y.

, whereis a constant

, whereis a constant

To find, use the initial condition,, and solve:

Therefore,y=2e^x.

Finally, at,y(2)=2e^2.

Example Question #21 :Integrals

Solve the differential equation:

Note thatis on the curve.

Possible Answers:

有限公司rrect answer:

解释:

In order to solve differential equations, you must separate the variables first.

Since pointis on the curve,.

To get rid of the log, raise every term to the power of e:

Example Question #1 :Applications Of Antidifferentiation

Suppose $1000 is invested in an account that pays 4.3% interest compounded continuously. Find an expression for the amount in the account after time.

Possible Answers:

y(t)=1000e^{t}

y(t)=4.3e^{1000t}

y(t)=1000e^{0.043t}

y(t)=43e^{1000t}

y(t)=4.3e^{t}

有限公司rrect answer:

y(t)=1000e^{0.043t}

解释:

The differential equation is\frac{dy}{dt}=0.043y, with boundary conditiony(0)=1000.

This is a separable first order differential equation.

\frac{1}{y}dy=0.043dt

Integrate both sides.

ln(y)=0.043t+c

y=Ce^{0.043t}

Plug in the initial condition above to see that.

Example Question #8 :Solving Separable Differential Equations And Using Them In Modeling

Find the solution to the differential equation

when.

Possible Answers:

有限公司rrect answer:

解释:

First, separate the variables of the original differential equation:

.

Then, take the antiderivative of both sides, which gives

.

Use the given condition, plugging in

and, to solve for. This gives, so the correct answer is

.

Example Question #2 :Applications Of Antidifferentiation

Differentiate.

Possible Answers:

有限公司rrect answer:

解释:

While differentiating, multiply the exponent with the coefficient then subtract the exponent by one.

←之前 1 3 4
Learning Tools by Varsity Tutors