Calculus 1 : Equations

Study concepts, example questions & explanations for Calculus 1

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Example Questions

Example Question #81 : Equations

Evaluate the following indefinite integral:

\(\displaystyle \int (2x+3)dx\)

Possible Answers:

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

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

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

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

Correct answer:

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

Explanation:

To evaluate the integral, use the inverse power rule:

\(\displaystyle \int x^{n}dx=\frac{x^{n+1}}{n+1} n\neq1\)

Applying that rule to this problem gives us the following for the first term:

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

And the following for the second term:

\(\displaystyle \frac{3x^{0+1}}{0+1}=\frac{3x^{1}}{1}=3x\)

We can combine these terms and add our "C" to get the final answer:

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

Example Question #82 : Equations

Evaluate the following indefinite integral:

\(\displaystyle \int (56x^{6}+9x^{2})dx\)

Possible Answers:

\(\displaystyle 8x^{7}+3x^{3}+C\)

\(\displaystyle 7x^{7}+9x^{3}\)

\(\displaystyle 8x^{7}+3x^{3}\)

\(\displaystyle 7x^{7}+9x^{3}+C\)

Correct answer:

\(\displaystyle 8x^{7}+3x^{3}+C\)

Explanation:

To evaluate the integral, use the inverse power rule:

\(\displaystyle \int x^{n}dx=\frac{x^{n+1}}{n+1} n\neq1\)

Applying that rule to this problem gives us the following for the first term:

\(\displaystyle \frac{56x^{6+1}}{6+1}=\frac{56x^{7}}{7}=8x^{7}\)

And the following for the second term:

\(\displaystyle \frac{9x^{2+1}}{2+1}=\frac{9x^{3}}{3}=3x^{3}\)

We can combine these terms and add our "C" to get the final answer:

\(\displaystyle 8x^{7}+3x^{3}+C\)

Example Question #83 : Equations

Evaluate the following indefinite integral:

\(\displaystyle \int (12x^{4}-6x^{2}-9)dx\)

Possible Answers:

\(\displaystyle 12x^{5}-2x^{3}-9x+C\)

\(\displaystyle \frac{12x^{5}}{5}-2x^{3}-9x+C\)

\(\displaystyle \frac{12x^{5}}{5}+2x^{3}-9x+C\)

\(\displaystyle 5x^{5}+2x^{3}-9x+C\)

Correct answer:

\(\displaystyle \frac{12x^{5}}{5}-2x^{3}-9x+C\)

Explanation:

To evaluate the integral, use the inverse power rule:

\(\displaystyle \int x^{n}dx=\frac{x^{n+1}}{n+1} n\neq1\)

Applying that rule to this problem gives us the following for the first term:

\(\displaystyle \frac{12x^{4+1}}{4+1}=\frac{12x^{5}}{5}\)

The following for the second term:

\(\displaystyle \frac{-6x^{2+1}}{2+1}=\frac{-6x^{3}}{3}=-2x^{3}\)

And the following for our thrid term:

\(\displaystyle \frac{-9x^{0+1}}{0+1}=\frac{-9x^{1}}{1}=-9x\)

We can combine these terms and add our "C" to get the final answer:

\(\displaystyle \frac{12x^{5}}{5}-2x^{3}-9x+C\)

Example Question #81 : Equations

Evaluate the following indefinite integral:

\(\displaystyle \int 15x^{2}dx\)

Possible Answers:

\(\displaystyle 5x^{2}+C\)

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

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

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

Correct answer:

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

Explanation:

To evaluate the integral, use the inverse power rule:

\(\displaystyle \int x^{n}dx=\frac{x^{n+1}}{n+1} n\neq1\)

Applying that rule to this problem gives us the following for the first term:

\(\displaystyle \frac{15x^{2+1}}{2+1}=\frac{15x^{3}}{3}=5x^{3}\)

Add our "C" to get the final answer:

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

Example Question #85 : Equations

Evaluate the following indefinite integral:

\(\displaystyle \int cos(x+3)dx\)

Possible Answers:

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

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

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

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

Correct answer:

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

Explanation:

To evaluate this integral we have to remember the laws of trig functions. In this problem we also use a "u substitution" to account for the function inside of the cosine. The steps for a "u-sub" are as follows:

1. Set the function equal to u and take the derivative of both sides.

\(\displaystyle u=x+3\)

\(\displaystyle du=dx\) 

2. Substitute each of the x values for u values in the integral then solve the integral:

\(\displaystyle \int cos(x+3)dx=\int cos(u)du= sin(u)+C\)

3. Put the x values back into the equation to get the final answer:

\(\displaystyle sin(u)+C = sin(x+3)+C\)

 

 

Example Question #86 : Equations

Evaluate the following indefinite integral:

\(\displaystyle \int 6(2x+6)^{2}dx\)

Possible Answers:

\(\displaystyle (2x+6)^{2}+C\)

\(\displaystyle 3(2x+6)^{3}+C\)

\(\displaystyle (2x+6)^{3}+C\)

\(\displaystyle \frac{(2x+6)^{3}}{3}+C\)

Correct answer:

\(\displaystyle (2x+6)^{3}+C\)

Explanation:

In this problem we use a "u substitution" to account for the function inside of the parentheses. The steps for a "u-sub" are as follows:

1. Set the function equal to u, take the derivative of both sides, and solve for dx:

\(\displaystyle u=2x+6\)

\(\displaystyle du=2dx\)

\(\displaystyle dx=\frac{du}{2}\)

2. Substitute each of the x values for u values in the integral then solve accordingly:

\(\displaystyle \int 6(u)^{2}*\frac{du}{2}= \int3u^{2}du\)

\(\displaystyle \int3u^{2}du=\frac{3u^{2+1}}{2+1}=\frac{3u^{3}}{3}=u^{3}\)

3. Put the x values back into the equation and add "C" to get the final answer:

\(\displaystyle u^{3}=(2x+6)^{3}+C\)

Example Question #87 : Equations

Evaluate the following indefinite integral:

\(\displaystyle \int (cos(x))^{2}sin(x)dx\)

 

Possible Answers:

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

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

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

\(\displaystyle (cos(x))^{3}+C\)

Correct answer:

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

Explanation:

In this problem we use a "u substitution" to account for the function inside of the parentheses. The steps for a "u-sub" are as follows:

1. Set the function equal to u, take the derivative of both sides, and solve for dx:

\(\displaystyle u=cos(x)dx\)

\(\displaystyle du=-sin(x)dx\)

\(\displaystyle -du=sin(x)dx\)

2. Substitute each of the x values for u values in the integral then solve accordingly:

\(\displaystyle \int u^{2}*-du= \int -u^{2}du\)

\(\displaystyle \int -u^{2}du=\frac{-u^{2+1}}{2+1}=\frac{-u^{3}}{3}\)

3. Put the x values back into the equation and add "C" to get the final answer:

\(\displaystyle \frac{-u^{3}}{3}=\frac{-(cos(x))^{3}}{3}+C\)

Example Question #82 : Writing Equations

Evaluate the following indefinite integral:

\(\displaystyle \int (2x+5)^{2}dx\)

Possible Answers:

\(\displaystyle \frac{(2x+5)^{3}}{6}+C\)

\(\displaystyle (2x+5)^{3}+C\)

\(\displaystyle \frac{(2x+5)^{3}}{3}+C\)

\(\displaystyle \frac{(2x+5)^{3}}{2}+C\)

Correct answer:

\(\displaystyle \frac{(2x+5)^{3}}{6}+C\)

Explanation:

In this problem we use a "u substitution" to account for the function inside of the parentheses. The steps for a "u-sub" are as follows:

1. Set the function equal to u, take the derivative of both sides, and solve for dx:

\(\displaystyle u=2x+5\)

\(\displaystyle du=2dx\)

\(\displaystyle \frac{du}{2}=dx\)

2. Substitute each of the x values for u values in the integral then solve accordingly:

\(\displaystyle \int u^{2}*\frac{du}{2}=\int \frac{u^{2}}{2}du\)

\(\displaystyle \int \frac{u^{2}}{2}du=\frac{u^{2+1}}{2*(2+1)}=\frac{u^{3}}{2*3}=\frac{u^{3}}{6}\)

3. Put the x values back into the equation and add "C" to get the final answer:

\(\displaystyle \frac{u^{3}}{6}=\frac{(2x+5)^{3}}{6}+C\)

Example Question #89 : Equations

Evaluate the following indefinite integral:

\(\displaystyle \int 12(4x+2)^{3}dx\)

Possible Answers:

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

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

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

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

Correct answer:

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

Explanation:

In this problem we use a "u substitution" to account for the function inside of the parentheses. The steps for a "u-sub" are as follows:

1. Set the function equal to u, take the derivative of both sides, and solve for dx:

\(\displaystyle u=4x+2\)

\(\displaystyle du=4dx\)

\(\displaystyle dx=\frac{du}{4}\)

2. Substitute each of the x values for u values in the integral then solve accordingly:

\(\displaystyle \int 12u^{3}*\frac{du}{4}= \int 3u^{3}du\)

\(\displaystyle \int 3u^{3}du= \frac{3u^{3+1}}{3+1}=\frac{3u^{4}}{4}\)

3. Put the x values back into the equation and add "C" to get the final answer:

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

Example Question #90 : Equations

Evaluate the following indefinite integral:

\(\displaystyle \int (x+6)^{2}dx\)

Possible Answers:

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

\(\displaystyle \frac{2}{3}(x+6)^{3}+C\)

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

\(\displaystyle \frac{2}{3}(x+6)^{2}+C\)

Correct answer:

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

Explanation:

In this problem we use a "u substitution" to account for the function inside of the parentheses. The steps for a "u-sub" are as follows:

1. Set the function equal to u, take the derivative of both sides, and solve for dx:

\(\displaystyle u=x+6\)

\(\displaystyle du=dx\)

2. Substitute each of the x values for u values in the integral then solve accordingly:

\(\displaystyle \int u^{2}du = \frac{u^{2+1}}{2+1}=\frac{u^{3}}{3}\)

3. Put the x values back into the equation and add "C" to get the final answer:

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

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