AP Calculus AB : Functions, Graphs, and Limits

Study concepts, example questions & explanations for AP Calculus AB

varsity tutors app store varsity tutors android store

Example Questions

Example Question #11 : Comparing Relative Magnitudes Of Functions And Their Rates Of Change

Evaluate the following definite integral.

\displaystyle \int_{1}^{3}6xdx

Possible Answers:

\displaystyle 6

\displaystyle 24

\displaystyle 3x^2+C

\displaystyle 6x^2

\displaystyle 27

Correct answer:

\displaystyle 24

Explanation:

Unlike an indefinite integral, the definite integral must be evaluated at its limits, in this case, from 1 to 3.  First, we use our inverse power rule to find the antiderivative. So, we have that \displaystyle \int x^ndx=\frac{x^{n+1}}{n+1}.  Once you find the antiderivative, we must remember that  int_a^bf(z)dz=F(b)-F(a).  where \displaystyle F is the indefinite integral.  So, we plug in our limits and subtract the two.  So, we have \displaystyle (3x^2)|_1^3=3(3^2)-3(1^2)=24.

Example Question #249 : Ap Calculus Ab

Evaluate the following definite integral.

\displaystyle \int_{1}^{4}\frac{1}{x}dx

Possible Answers:

\displaystyle 2x^2

\displaystyle ln\ 4

\displaystyle ln\ 1

\displaystyle 3

\displaystyle ln\ 3

Correct answer:

\displaystyle ln\ 4

Explanation:

Unlike an indefinite integral, the definite integral must be evaluated at its limits, in this case, from 1 to 4.  First, we use our inverse power rule to find the antiderivative. So since \displaystyle x is to the power of \displaystyle -1, we have that \displaystyle \int x^{-1}=ln|x|.  Once you find the antiderivative, we must remember that  int_a^bf(z)dz=F(b)-F(a).  where \displaystyle F is the indefinite integral.  So, we plug in our limits and subtract the two.  So, we have \displaystyle ln(x)|_1^4=ln(4)-ln(1)=ln(4) because we know that \displaystyle ln\ 1=0.

Example Question #32 : Asymptotic And Unbounded Behavior

Evaluate the following indefinite integral.

\displaystyle \int 4xdx

Possible Answers:

\displaystyle 4

\displaystyle x^2+C

\displaystyle 8x^2+C

\displaystyle 2x^2+C

\displaystyle (1/2)x^2

Correct answer:

\displaystyle 2x^2+C

Explanation:

First, we know that we can pull the constant "4" out of the integral, and we then evaluate the integral according to this equation:

\displaystyle \int x^n dx=\frac{x^{n+1}}{n+1}+C, n\ne1. From this, we acquire the answer above.  As a note, we cannot forget the constant of integration \displaystyle C which would be lost during the differentiation.

Example Question #36 : Asymptotic And Unbounded Behavior

Evaluate the following indefinite integral.

\displaystyle \int (6x+3x^2+4)dx

Possible Answers:

\displaystyle x^2+x^3+4x+C

\displaystyle 3x^2+x^3+4x

\displaystyle \frac{1}{3}x^2+x^3+\frac{1}{4}x+C

\displaystyle 6+3x+C

\displaystyle 3x^2+x^3+4x+C

Correct answer:

\displaystyle 3x^2+x^3+4x+C

Explanation:

First, we know that the integral of a sum is the same as the sum of the integrals, so if needed, we can split the three integrals up and evaluate them seperately.  We then evaluate each integral according to this equation:

\displaystyle \int x^n dx=\frac{x^{n+1}}{n+1}+C, n\ne1. From this, we acquire the answer above.  As a note, we cannot forget the constant of integration \displaystyle C which would be lost during the differentiation.

Example Question #33 : Asymptotic And Unbounded Behavior

Evalulate the following indefinite integral.

\displaystyle \int \frac{1}{x}dx

Possible Answers:

\displaystyle -1/x^2+C

\displaystyle ln(x)+C

\displaystyle e^x\displaystyle +C

\displaystyle 1/2 x^{-2}

\displaystyle 1/2 x^{-2}+C

Correct answer:

\displaystyle ln(x)+C

Explanation:

Normally, we would evalute the indefinite integral according to the following equation:

\displaystyle \int x^n dx=\frac{x^{n+1}}{n+1}+C, n\ne1. However, in this case, \displaystyle n=-1.  Now we use our other rule that states the integral of \displaystyle \frac{1}{x} is equal to \displaystyle \ln (x) plus a constant.  From this, we acquire the answer above.  As a note, we cannot forget the constant of integration \displaystyle C which would be lost during the differentiation.

Example Question #41 : Asymptotic And Unbounded Behavior

Evaluate the following indefinite integral.

\displaystyle \int\frac{1}{x^2}dx

Possible Answers:

\displaystyle 3x^3+C

\displaystyle -x^{-1}+C

 

\displaystyle (1/2)ln(x)+C

\displaystyle 2ln(x)+C

\displaystyle \frac{-1}{3x^3}+C

Correct answer:

\displaystyle -x^{-1}+C

 

Explanation:

We evaluate the integral according to this equation:

\displaystyle \int x^n dx=\frac{x^{n+1}}{n+1}+C, n\ne1. From this, we acquire the answer above. Keep in mind that \displaystyle \frac{1}{x^{2}} is the same as \displaystyle x^{-2}.  As a note, we cannot forget the constant of integration \displaystyle C which would be lost during the differentiation.

Example Question #41 : Asymptotic And Unbounded Behavior

Evaluate the following indefinite integral.

\displaystyle \int(3x^7+4x^4)dx

Possible Answers:

\displaystyle \frac{8}{3}x^8+\frac{5}{4}x^5+C

\displaystyle 3x^6+4x^3+C

\displaystyle 8x^8+5x^5+C

\displaystyle \frac{1}{8}x^8+\frac{1}{5}x^5+C

\displaystyle \frac{3}{8}x^8+\frac{4}{5}x^5+C

Correct answer:

\displaystyle \frac{3}{8}x^8+\frac{4}{5}x^5+C

Explanation:

First, we remember that the integral of a sum is the same as the sum of the integrals, so we can split the sum into seperate integrals and solve them individually.  We then evaluate each integral according to this equation:

\displaystyle \int x^n dx=\frac{x^{n+1}}{n+1}+C, n\ne1. From this, we acquire the answer above.  As a note, we cannot forget the constant of integration \displaystyle C which would be lost during the differentiation.

Example Question #42 : Asymptotic And Unbounded Behavior

Evaluate the following indefinite integral.

\displaystyle \int\frac{1}{2}x^2dx

Possible Answers:

\displaystyle \frac{1}{2}x^3+C

\displaystyle 3x^3+C

\displaystyle 6x^3+C

\displaystyle \frac{1}{2}x^3+C

\displaystyle \frac{1}{6}x^3+C

Correct answer:

\displaystyle \frac{1}{6}x^3+C

Explanation:

First, we know that we can pull the constant \displaystyle \frac{1}{2} out of the integral, and we then evaluate the integral according to this equation:

\displaystyle \int x^n dx=\frac{x^{n+1}}{n+1}+C, n\ne1. From this, we acquire the answer above.  As a note, we cannot forget the constant of integration \displaystyle C which would be lost during the differentiation.

Example Question #44 : Asymptotic And Unbounded Behavior

Evaluate the following indefinite integral.

\displaystyle \int \frac{3}{5}x^3dx

Possible Answers:

\displaystyle \frac{20}{3}x^4+C

\displaystyle \frac{3}{15}x^4+C

\displaystyle \frac{3}{20}x^4+C

\displaystyle \frac{9}{5}x^4+C

\displaystyle \frac{1}{20}x^4+C

Correct answer:

\displaystyle \frac{3}{20}x^4+C

Explanation:

First, we know that we can pull the constant \displaystyle \frac{3}{5} out of the integral, and we then evaluate the integral according to this equation:

\displaystyle \int x^n dx=\frac{x^{n+1}}{n+1}+C, n\ne1. From this, we acquire the answer above.  As a note, we cannot forget the constant of integration \displaystyle C which would be lost during the differentiation.

Example Question #43 : Asymptotic And Unbounded Behavior

Evaluate the following indefinite integral.

\displaystyle \int\sqrt{x}dx

Possible Answers:

\displaystyle e^x+C

\displaystyle ln(x)+C

\displaystyle \frac{1}{3}x^{\frac{1}{2}}+C

\displaystyle 3x^{-1/2}+C

\displaystyle \frac{2}{3}x^{\frac{3}{2}}+C

Correct answer:

\displaystyle \frac{2}{3}x^{\frac{3}{2}}+C

Explanation:

We evaluate the integral according to this equation:

\displaystyle \int x^n dx=\frac{x^{n+1}}{n+1}+C, n\ne1. Keep in mind that \displaystyle \sqrt{x} is the same as \displaystyle x^{1/2}. From this, we acquire the answer above.  As a note, we cannot forget the constant of integration \displaystyle C which would be lost during the differentiation.

Learning Tools by Varsity Tutors