AP Calculus AB : Functions, Graphs, and Limits

Study concepts, example questions & explanations for AP Calculus AB

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Example Questions

Example Question #41 : Functions, Graphs, And Limits

Evaluate the following definite integral.

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

Possible Answers:

\(\displaystyle 6x^2\)

\(\displaystyle 6\)

\(\displaystyle 3x^2+C\)

\(\displaystyle 24\)

\(\displaystyle 27\)

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 #42 : Functions, Graphs, And Limits

Evaluate the following definite integral.

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

Possible Answers:

\(\displaystyle 3\)

\(\displaystyle ln\ 1\)

\(\displaystyle ln\ 4\)

\(\displaystyle 2x^2\)

\(\displaystyle ln\ 3\)

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 #251 : Ap Calculus Ab

Evaluate the following indefinite integral.

\(\displaystyle \int 4xdx\)

Possible Answers:

\(\displaystyle x^2+C\)

\(\displaystyle (1/2)x^2\)

\(\displaystyle 8x^2+C\)

\(\displaystyle 4\)

\(\displaystyle 2x^2+C\)

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 #252 : Ap Calculus Ab

Evaluate the following indefinite integral.

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

Possible Answers:

\(\displaystyle 6+3x+C\)

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

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

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

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

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 #253 : Ap Calculus Ab

Evalulate the following indefinite integral.

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

Possible Answers:

\(\displaystyle ln(x)+C\)

\(\displaystyle -1/x^2+C\)

\(\displaystyle e^x\)\(\displaystyle +C\)

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

\(\displaystyle 1/2 x^{-2}\)

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 #254 : Ap Calculus Ab

Evaluate the following indefinite integral.

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

Possible Answers:

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

\(\displaystyle -x^{-1}+C\)

 

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

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

\(\displaystyle 3x^3+C\)

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 #255 : Ap Calculus Ab

Evaluate the following indefinite integral.

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

Possible Answers:

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

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

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

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

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

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 #256 : Ap Calculus Ab

Evaluate the following indefinite integral.

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

Possible Answers:

\(\displaystyle 3x^3+C\)

\(\displaystyle 6x^3+C\)

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

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

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

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 #257 : Ap Calculus Ab

Evaluate the following indefinite integral.

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

Possible Answers:

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

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

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

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

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

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 #258 : Ap Calculus Ab

Evaluate the following indefinite integral.

\(\displaystyle \int\sqrt{x}dx\)

Possible Answers:

\(\displaystyle e^x+C\)

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

\(\displaystyle ln(x)+C\)

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

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

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.

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