Calculus Examples

$\int \sqrt[3]{x} \ln (x) d x$

Step 1

Integrate by parts using the formula $\int u d v = u v - \int v d u$ , where $u = \ln (x)$ and $d v = \sqrt[3]{x}$ .

$\ln (x) (\frac{3}{4} x^{\frac{4}{3}}) - \int \frac{3}{4} x^{\frac{4}{3}} \frac{1}{x} d x$

Step 2

Simplify.

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Step 2.1

Combine $\frac{3}{4}$ and $x^{\frac{4}{3}}$ .

$\ln (x) \frac{3 x^{\frac{4}{3}}}{4} - \int \frac{3}{4} x^{\frac{4}{3}} \frac{1}{x} d x$

Step 2.2

Combine $\ln (x)$ and $\frac{3 x^{\frac{4}{3}}}{4}$ .

$\frac{\ln (x) (3 x^{\frac{4}{3}})}{4} - \int \frac{3}{4} x^{\frac{4}{3}} \frac{1}{x} d x$

Step 3

Since $\frac{3}{4}$ is constant with respect to $x$ , move $\frac{3}{4}$ out of the integral.

$\frac{\ln (x) (3 x^{\frac{4}{3}})}{4} - (\frac{3}{4} \int x^{\frac{4}{3}} \frac{1}{x} d x)$

Step 4

Simplify.

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Step 4.1

Combine $x^{\frac{4}{3}}$ and $\frac{1}{x}$ .

$\frac{\ln (x) (3 x^{\frac{4}{3}})}{4} - (\frac{3}{4} \int \frac{x^{\frac{4}{3}}}{x} d x)$

Step 4.2

Move $x^{1}$ to the numerator using the negative exponent rule $\frac{1}{b^{n}} = b^{- n}$ .

$\frac{\ln (x) (3 x^{\frac{4}{3}})}{4} - (\frac{3}{4} \int x^{\frac{4}{3}} x^{- 1} d x)$

Step 4.3

Multiply $x^{\frac{4}{3}}$ by $x^{- 1}$ by adding the exponents.

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Step 4.3.1

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$\frac{\ln (x) (3 x^{\frac{4}{3}})}{4} - (\frac{3}{4} \int x^{\frac{4}{3} - 1} d x)$

Step 4.3.2

To write $- 1$ as a fraction with a common denominator, multiply by $\frac{3}{3}$ .

$\frac{\ln (x) (3 x^{\frac{4}{3}})}{4} - (\frac{3}{4} \int x^{\frac{4}{3} - 1 \cdot \frac{3}{3}} d x)$

Step 4.3.3

Combine $- 1$ and $\frac{3}{3}$ .

$\frac{\ln (x) (3 x^{\frac{4}{3}})}{4} - (\frac{3}{4} \int x^{\frac{4}{3} + \frac{- 1 \cdot 3}{3}} d x)$

Step 4.3.4

Combine the numerators over the common denominator.

$\frac{\ln (x) (3 x^{\frac{4}{3}})}{4} - (\frac{3}{4} \int x^{\frac{4 - 1 \cdot 3}{3}} d x)$

Step 4.3.5

Simplify the numerator.

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Step 4.3.5.1

Multiply $- 1$ by $3$ .

$\frac{\ln (x) (3 x^{\frac{4}{3}})}{4} - (\frac{3}{4} \int x^{\frac{4 - 3}{3}} d x)$

Step 4.3.5.2

Subtract $3$ from $4$ .

$\frac{\ln (x) (3 x^{\frac{4}{3}})}{4} - (\frac{3}{4} \int x^{\frac{1}{3}} d x)$

$\frac{\ln (x) (3 x^{\frac{4}{3}})}{4} - \frac{3}{4} \int x^{\frac{1}{3}} d x$

Step 5

By the Power Rule, the integral of $x^{\frac{1}{3}}$ with respect to $x$ is $\frac{3}{4} x^{\frac{4}{3}}$ .

$\frac{\ln (x) (3 x^{\frac{4}{3}})}{4} - \frac{3}{4} (\frac{3}{4} x^{\frac{4}{3}} + C)$

Step 6

Simplify the answer.

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Step 6.1

Rewrite $\frac{\ln (x) (3 x^{\frac{4}{3}})}{4} - \frac{3}{4} (\frac{3}{4} x^{\frac{4}{3}} + C)$ as $\frac{3}{4} \ln (x) x^{\frac{4}{3}} - \frac{3}{4} \cdot \frac{3}{4} x^{\frac{4}{3}} + C$ .

$\frac{3}{4} \ln (x) x^{\frac{4}{3}} - \frac{3}{4} \cdot \frac{3}{4} x^{\frac{4}{3}} + C$

Step 6.2

Simplify.

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Step 6.2.1

Combine $\frac{3}{4}$ and $\ln (x)$ .

$\frac{3 \ln (x)}{4} x^{\frac{4}{3}} - \frac{3}{4} \cdot \frac{3}{4} x^{\frac{4}{3}} + C$

Step 6.2.2

Combine $\frac{3 \ln (x)}{4}$ and $x^{\frac{4}{3}}$ .

$\frac{3 \ln (x) x^{\frac{4}{3}}}{4} - \frac{3}{4} \cdot \frac{3}{4} x^{\frac{4}{3}} + C$

Step 6.2.3

Multiply $\frac{3}{4}$ by $\frac{3}{4}$ .

$\frac{3 \ln (x) x^{\frac{4}{3}}}{4} - \frac{3 \cdot 3}{4 \cdot 4} x^{\frac{4}{3}} + C$

Step 6.2.4

Multiply $3$ by $3$ .

$\frac{3 \ln (x) x^{\frac{4}{3}}}{4} - \frac{9}{4 \cdot 4} x^{\frac{4}{3}} + C$

Step 6.2.5

Multiply $4$ by $4$ .

$\frac{3 \ln (x) x^{\frac{4}{3}}}{4} - \frac{9}{16} x^{\frac{4}{3}} + C$

$\frac{3}{4} \ln (x) x^{\frac{4}{3}} - \frac{9}{16} x^{\frac{4}{3}} + C$