Calculus 2 : Integrals

Study concepts, example questions & explanations for Calculus 2

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Example Questions

Example Question #342 : Finding Integrals

Evaluate.

\(\displaystyle \int -\cos(7x) \ dx\)

Possible Answers:

\(\displaystyle F(x) = - \sin(7x)\)

\(\displaystyle F(x) = \frac{\sin(x)}{7}\)

\(\displaystyle F(x) = - \frac{\sin(7x)}{7}\)

Answer not listed.

\(\displaystyle F(x) = \frac{\cos(7x)}{7}\)

Correct answer:

\(\displaystyle F(x) = - \frac{\sin(7x)}{7}\)

Explanation:

\(\displaystyle \int f(x) \ dx\)

In order to evaluate this integral, first find the antiderivative of \(\displaystyle f(x).\)

If \(\displaystyle f(x) = a\) then \(\displaystyle F(x) = ax + C\)

If \(\displaystyle f(x) = x a\) then \(\displaystyle F(x) = \frac{x^{a+1}}{a+1} + C\)

If \(\displaystyle f(x) = \frac{1}{x}\) then \(\displaystyle F(x) = ln(x) + C\)

If \(\displaystyle f(x) = e ^x\) then \(\displaystyle F(x) = e^x + C\)

If \(\displaystyle f(x) = \cos(x)\) then \(\displaystyle F(x) = \sin(x) + C\)

If \(\displaystyle f(x) = \sin(x)\) then \(\displaystyle F(x) = - \cos(x) + C\)

If \(\displaystyle f(x) = \sec^2 (x)\) then \(\displaystyle F(x) = \tan(x) + C\)

 

 

In this case, \(\displaystyle f(x) =-\cos(7x)\).

The antiderivative is  \(\displaystyle F(x) = - \frac{\sin(7x)}{7}\).

Example Question #343 : Finding Integrals

Evaluate.

\(\displaystyle \int e^{2x-5} - \sin(2x-5) \ dx\)

Possible Answers:

\(\displaystyle F(x) = \frac{e^{2x-5}}{x} - \frac{\cos(2x-5)}{x}\)

\(\displaystyle F(x) = e^{2x-5}+ \cos(2x-5)\)

\(\displaystyle F(x) = \frac{e^{2x-5}}{2} + \frac{\cos(2x-5)}{2}\)

\(\displaystyle F(x) = \frac{e^{2x-5}}{e^2} + \frac{\cos(2x-5)}{\cos2}\)

Answer not listed.

Correct answer:

\(\displaystyle F(x) = \frac{e^{2x-5}}{2} + \frac{\cos(2x-5)}{2}\)

Explanation:

\(\displaystyle \int f(x) \ dx\)

In order to evaluate this integral, first find the antiderivative of \(\displaystyle f(x).\)

If \(\displaystyle f(x) = a\) then \(\displaystyle F(x) = ax + C\)

If \(\displaystyle f(x) = x a\) then \(\displaystyle F(x) = \frac{x^{a+1}}{a+1} + C\)

If \(\displaystyle f(x) = \frac{1}{x}\) then \(\displaystyle F(x) = ln(x) + C\)

If \(\displaystyle f(x) = e ^x\) then \(\displaystyle F(x) = e^x + C\)

If \(\displaystyle f(x) = \cos(x)\) then \(\displaystyle F(x) = \sin(x) + C\)

If \(\displaystyle f(x) = \sin(x)\) then \(\displaystyle F(x) = - \cos(x) + C\)

If \(\displaystyle f(x) = \sec^2 (x)\) then \(\displaystyle F(x) = \tan(x) + C\)

 

 

In this case, \(\displaystyle f(x) =e^{2x-5} - \sin(2x-5)\).

The antiderivative is  \(\displaystyle F(x) = \frac{e^{2x-5}}{2} + \frac{\cos(2x-5)}{2}\).

Example Question #344 : Finding Integrals

Evaluate.

\(\displaystyle \int 5x^4 + 12x \ dx\)

Possible Answers:

\(\displaystyle F(x) = 5x^5 + 12x^2\)

\(\displaystyle F(x) = \frac{1}{5}x^5 + \frac{1}{12}x^2\)

\(\displaystyle F(x) = x^5 + 6x^2\)

\(\displaystyle F(x) = 5x^4 + 12x\)

Answer not listed.

Correct answer:

\(\displaystyle F(x) = x^5 + 6x^2\)

Explanation:

\(\displaystyle \int f(x) \ dx\)

In order to evaluate this integral, first find the antiderivative of \(\displaystyle f(x).\)

If \(\displaystyle f(x) = a\) then \(\displaystyle F(x) = ax + C\)

If \(\displaystyle f(x) = x a\) then \(\displaystyle F(x) = \frac{x^{a+1}}{a+1} + C\)

If \(\displaystyle f(x) = \frac{1}{x}\) then \(\displaystyle F(x) = ln(x) + C\)

If \(\displaystyle f(x) = e ^x\) then \(\displaystyle F(x) = e^x + C\)

If \(\displaystyle f(x) = \cos(x)\) then \(\displaystyle F(x) = \sin(x) + C\)

If \(\displaystyle f(x) = \sin(x)\) then \(\displaystyle F(x) = - \cos(x) + C\)

If \(\displaystyle f(x) = \sec^2 (x)\) then \(\displaystyle F(x) = \tan(x) + C\)

 

 

In this case, \(\displaystyle f(x) =5x^4 + 12x\).

The antiderivative is  \(\displaystyle F(x) = x^5 + 6x^2\).

Example Question #345 : Finding Integrals

Evaluate.

\(\displaystyle \int \frac{4}{x-1} \ dx\)

Possible Answers:

\(\displaystyle F(x) =\frac{\ln(x-1)}{4}\)

\(\displaystyle F(x) = \ln(x-1)\)

Answer not listed.

\(\displaystyle F(x) = 4 \ln(x-1)\)

\(\displaystyle F(x) = \frac{1}{ \ln(x-1)}\)

Correct answer:

\(\displaystyle F(x) = 4 \ln(x-1)\)

Explanation:

\(\displaystyle \int f(x) \ dx\)

In order to evaluate this integral, first find the antiderivative of \(\displaystyle f(x).\)

If \(\displaystyle f(x) = a\) then \(\displaystyle F(x) = ax + C\)

If \(\displaystyle f(x) = x a\) then \(\displaystyle F(x) = \frac{x^{a+1}}{a+1} + C\)

If \(\displaystyle f(x) = \frac{1}{x}\) then \(\displaystyle F(x) = ln(x) + C\)

If \(\displaystyle f(x) = e ^x\) then \(\displaystyle F(x) = e^x + C\)

If \(\displaystyle f(x) = \cos(x)\) then \(\displaystyle F(x) = \sin(x) + C\)

If \(\displaystyle f(x) = \sin(x)\) then \(\displaystyle F(x) = - \cos(x) + C\)

If \(\displaystyle f(x) = \sec^2 (x)\) then \(\displaystyle F(x) = \tan(x) + C\)

 

In this case, \(\displaystyle f(x) = \frac{4}{x-1}\).

The antiderivative is  \(\displaystyle F(x) = 4 \ln(x-1)\).

Example Question #346 : Finding Integrals

Evaluate.

\(\displaystyle \int 12 \ dx\)

Possible Answers:

\(\displaystyle F(x) = 12x\)

\(\displaystyle F(x) = 12x^2\)

\(\displaystyle F(x) =0\)

Answer not listed

\(\displaystyle F(x) = \frac{1}{12}x\)

Correct answer:

\(\displaystyle F(x) = 12x\)

Explanation:

\(\displaystyle \int f(x) \ dx\)

In order to evaluate this integral, first find the antiderivative of \(\displaystyle f(x).\)

If \(\displaystyle f(x) = a\) then \(\displaystyle F(x) = ax + C\)

If \(\displaystyle f(x) = x a\) then \(\displaystyle F(x) = \frac{x^{a+1}}{a+1} + C\)

If \(\displaystyle f(x) = \frac{1}{x}\) then \(\displaystyle F(x) = ln(x) + C\)

If \(\displaystyle f(x) = e ^x\) then \(\displaystyle F(x) = e^x + C\)

If \(\displaystyle f(x) = \cos(x)\) then \(\displaystyle F(x) = \sin(x) + C\)

If \(\displaystyle f(x) = \sin(x)\) then \(\displaystyle F(x) = - \cos(x) + C\)

If \(\displaystyle f(x) = \sec^2 (x)\) then \(\displaystyle F(x) = \tan(x) + C\)

 

In this case, \(\displaystyle f(x) = 12\).

The antiderivative is  \(\displaystyle F(x) = 12x\).

Example Question #347 : Finding Integrals

Evaluate.

\(\displaystyle \int -\sin(6x) +3 \ dx\)

Possible Answers:

Answer not listed.

\(\displaystyle F(x) = \frac{\cos(6x)}{6} + 3x\)

\(\displaystyle F(x) = \frac{\cos(x)}{6x} + 3\)

\(\displaystyle F(x) = -\cos(6x) + 3x\)

\(\displaystyle F(x) =- \frac{\cos(6x)}{6} + 3x\)

Correct answer:

\(\displaystyle F(x) = \frac{\cos(6x)}{6} + 3x\)

Explanation:

\(\displaystyle \int f(x) \ dx\)

In order to evaluate this integral, first find the antiderivative of \(\displaystyle f(x).\)

If \(\displaystyle f(x) = a\) then \(\displaystyle F(x) = ax + C\)

If \(\displaystyle f(x) = x a\) then \(\displaystyle F(x) = \frac{x^{a+1}}{a+1} + C\)

If \(\displaystyle f(x) = \frac{1}{x}\) then \(\displaystyle F(x) = ln(x) + C\)

If \(\displaystyle f(x) = e ^x\) then \(\displaystyle F(x) = e^x + C\)

If \(\displaystyle f(x) = \cos(x)\) then \(\displaystyle F(x) = \sin(x) + C\)

If \(\displaystyle f(x) = \sin(x)\) then \(\displaystyle F(x) = - \cos(x) + C\)

If \(\displaystyle f(x) = \sec^2 (x)\) then \(\displaystyle F(x) = \tan(x) + C\)

 

In this case, \(\displaystyle f(x) = -\sin(6x) +3\).

The antiderivative is  \(\displaystyle F(x) = \frac{\cos(6x)}{6} + 3x\).

Example Question #348 : Finding Integrals

Evaluate.

\(\displaystyle \int 2x - \frac{1}{3x} \ dx\)

Possible Answers:

\(\displaystyle F(x) = x^2 - \frac{\ln(x)}{3}\)

Answer not listed.

\(\displaystyle F(x) = 2x^2 - \frac{\ln(3x)}{3}\)

\(\displaystyle F(x) = 2x^2 - \ln(x)\)

\(\displaystyle F(x) = \frac{1}{2}x^2 - \ln(x)\)

Correct answer:

\(\displaystyle F(x) = x^2 - \frac{\ln(x)}{3}\)

Explanation:

\(\displaystyle \int f(x) \ dx\)

In order to evaluate this integral, first find the antiderivative of \(\displaystyle f(x).\)

If \(\displaystyle f(x) = a\) then \(\displaystyle F(x) = ax + C\)

If \(\displaystyle f(x) = x a\) then \(\displaystyle F(x) = \frac{x^{a+1}}{a+1} + C\)

If \(\displaystyle f(x) = \frac{1}{x}\) then \(\displaystyle F(x) = ln(x) + C\)

If \(\displaystyle f(x) = e ^x\) then \(\displaystyle F(x) = e^x + C\)

If \(\displaystyle f(x) = \cos(x)\) then \(\displaystyle F(x) = \sin(x) + C\)

If \(\displaystyle f(x) = \sin(x)\) then \(\displaystyle F(x) = - \cos(x) + C\)

If \(\displaystyle f(x) = \sec^2 (x)\) then \(\displaystyle F(x) = \tan(x) + C\)

 

In this case, \(\displaystyle f(x) = 2x - \frac{1}{3x}\).

The antiderivative is  \(\displaystyle F(x) = x^2 - \frac{\ln(x)}{3}\).

Example Question #691 : Integrals

Evaluate.

\(\displaystyle \int e^{7x} - 7 \ dx\)

Possible Answers:

Answer not listed.

\(\displaystyle F(x) = 7e^{7x}\)

\(\displaystyle F(x) = 7e^{7x} - 7\)

\(\displaystyle F(x) = \frac{e^{7x}}{7} - 7x\)

\(\displaystyle F(x) = e^{7x} - 7\)

Correct answer:

\(\displaystyle F(x) = \frac{e^{7x}}{7} - 7x\)

Explanation:

\(\displaystyle \int f(x) \ dx\)

In order to evaluate this integral, first find the antiderivative of \(\displaystyle f(x).\)

If \(\displaystyle f(x) = a\) then \(\displaystyle F(x) = ax + C\)

If \(\displaystyle f(x) = x a\) then \(\displaystyle F(x) = \frac{x^{a+1}}{a+1} + C\)

If \(\displaystyle f(x) = \frac{1}{x}\) then \(\displaystyle F(x) = ln(x) + C\)

If \(\displaystyle f(x) = e ^x\) then \(\displaystyle F(x) = e^x + C\)

If \(\displaystyle f(x) = \cos(x)\) then \(\displaystyle F(x) = \sin(x) + C\)

If \(\displaystyle f(x) = \sin(x)\) then \(\displaystyle F(x) = - \cos(x) + C\)

If \(\displaystyle f(x) = \sec^2 (x)\) then \(\displaystyle F(x) = \tan(x) + C\)

 

In this case, \(\displaystyle f(x) = e^{7x} + 7\).

The antiderivative is  \(\displaystyle F(x) = \frac{e^{7x}}{7} - 7x\).

Example Question #72 : Indefinite Integrals

Evaluate.

\(\displaystyle \int \sin(x) + 6 - \frac{1}{5x}\ dx\)

Possible Answers:

\(\displaystyle F(x) = - \cos(x) + 6x - 5\ln (x)\)

\(\displaystyle F(x) = - \cos(x) + 6x - \frac{\ln (x)}{5}\)

Answer not listed.

\(\displaystyle F(x) = - \cos(x) + 6 - \frac{\ln (5x)}{5}\)

\(\displaystyle F(x) = - \sin(x) + 6x - \frac{\ln (5x)}{5}\)

Correct answer:

\(\displaystyle F(x) = - \cos(x) + 6x - \frac{\ln (x)}{5}\)

Explanation:

 \(\displaystyle f(x) = a\) then \(\displaystyle F(x) = ax + C\)

If \(\displaystyle f(x) = x a\) then \(\displaystyle F(x) = \frac{x^{a+1}}{a+1} + C\)

If \(\displaystyle f(x) = \frac{1}{x}\) then \(\displaystyle F(x) = ln(x) + C\)

If \(\displaystyle f(x) = e ^x\) then \(\displaystyle F(x) = e^x + C\)

If \(\displaystyle f(x) = \cos(x)\) then \(\displaystyle F(x) = \sin(x) + C\)

If \(\displaystyle f(x) = \sin(x)\) then \(\displaystyle F(x) = - \cos(x) + C\)

If \(\displaystyle f(x) = \sec^2 (x)\) then \(\displaystyle F(x) = \tan(x) + C\)

 

In this case, \(\displaystyle f(x) = \sin(x) + 6 - \frac{1}{5x}\).

The antiderivative is  \(\displaystyle F(x) = - \cos(x) + 6x - \frac{\ln (x)}{5}\).

Example Question #692 : Integrals

\(\displaystyle \int \frac{2x^2-8x+2}{2}dx\)

Possible Answers:

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

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

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

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

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

Correct answer:

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

Explanation:

First, make the fraction three separate terms: \(\displaystyle \int x^2-4x+1dx\). Now, integrate as normal, remembering to raise the exponent by 1 and then also putting that result on the denominator: \(\displaystyle \frac{x^3}{3}-2x^2+x\). Remember to add a C at the end because it is an indefinite integral: \(\displaystyle \frac{x^3}{3}-2x^2+x+C\).

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