Calculus Examples

$\int \frac{\ln (3 x)}{x^{2}} d x$

Step 1

Apply basic rules of exponents.

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Step 1.1

Move $x^{2}$ out of the denominator by raising it to the $- 1$ power.

$\int \ln (3 x) {(x^{2})}^{- 1} d x$

Step 1.2

Multiply the exponents in ${(x^{2})}^{- 1}$ .

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Step 1.2.1

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$\int \ln (3 x) x^{2 \cdot - 1} d x$

Step 1.2.2

Multiply $2$ by $- 1$ .

$\int \ln (3 x) x^{- 2} d x$

Step 2

Integrate by parts using the formula $\int u d v = u v - \int v d u$ , where $u = \ln (3 x)$ and $d v = x^{- 2}$ .

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

Step 3

Simplify.

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Step 3.1

Combine $\ln (3 x)$ and $\frac{1}{x}$ .

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

Step 3.2

Multiply $\frac{1}{x}$ by $\frac{1}{x}$ .

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

Step 3.3

Raise $x$ to the power of $1$ .

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

Step 3.4

Raise $x$ to the power of $1$ .

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

Step 3.5

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

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

Step 3.6

Add $1$ and $1$ .

$- \frac{\ln (3 x)}{x} - \int - \frac{1}{x^{2}} d x$

Step 4

Since $- 1$ is constant with respect to $x$ , move $- 1$ out of the integral.

$- \frac{\ln (3 x)}{x} - - \int \frac{1}{x^{2}} d x$

Step 5

Simplify the expression.

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Step 5.1

Simplify.

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Step 5.1.1

Multiply $- 1$ by $- 1$ .

$- \frac{\ln (3 x)}{x} + 1 \int \frac{1}{x^{2}} d x$

Step 5.1.2

Multiply $\int \frac{1}{x^{2}} d x$ by $1$ .

$- \frac{\ln (3 x)}{x} + \int \frac{1}{x^{2}} d x$

Step 5.2

Apply basic rules of exponents.

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Step 5.2.1

Move $x^{2}$ out of the denominator by raising it to the $- 1$ power.

$- \frac{\ln (3 x)}{x} + \int {(x^{2})}^{- 1} d x$

Step 5.2.2

Multiply the exponents in ${(x^{2})}^{- 1}$ .

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Step 5.2.2.1

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$- \frac{\ln (3 x)}{x} + \int x^{2 \cdot - 1} d x$

Step 5.2.2.2

Multiply $2$ by $- 1$ .

$- \frac{\ln (3 x)}{x} + \int x^{- 2} d x$

Step 6

By the Power Rule, the integral of $x^{- 2}$ with respect to $x$ is $- x^{- 1}$ .

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

Step 7

Rewrite $- \frac{\ln (3 x)}{x} - x^{- 1} + C$ as $- \frac{\ln (3 x)}{x} - \frac{1}{x} + C$ .

$- \frac{\ln (3 x)}{x} - \frac{1}{x} + C$