Calculus Examples

$\frac{\ln (3 x)}{x}$

Step 1

Differentiate using the Quotient Rule which states that $\frac{d}{d x} [\frac{f (x)}{g (x)}]$ is $\frac{g (x) \frac{d}{d x} [f (x)] - f (x) \frac{d}{d x} [g (x)]}{{g (x)}^{2}}$ where $f (x) = \ln (3 x)$ and $g (x) = x$ .

$\frac{x \frac{d}{d x} [\ln (3 x)] - \ln (3 x) \frac{d}{d x} [x]}{x^{2}}$

Step 2

Differentiate using the chain rule, which states that $\frac{d}{d x} [f (g (x))]$ is $f' (g (x)) g' (x)$ where $f (x) = \ln (x)$ and $g (x) = 3 x$ .

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Step 2.1

To apply the Chain Rule, set $u$ as $3 x$ .

$\frac{x (\frac{d}{d u} [\ln (u)] \frac{d}{d x} [3 x]) - \ln (3 x) \frac{d}{d x} [x]}{x^{2}}$

Step 2.2

The derivative of $\ln (u)$ with respect to $u$ is $\frac{1}{u}$ .

$\frac{x (\frac{1}{u} \frac{d}{d x} [3 x]) - \ln (3 x) \frac{d}{d x} [x]}{x^{2}}$

Step 2.3

Replace all occurrences of $u$ with $3 x$ .

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

Step 3

Differentiate.

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Step 3.1

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

$\frac{\frac{x}{3 x} \frac{d}{d x} [3 x] - \ln (3 x) \frac{d}{d x} [x]}{x^{2}}$

Step 3.2

Cancel the common factor of $x$ .

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Step 3.2.1

Cancel the common factor.

$\frac{\frac{x}{3 x} \frac{d}{d x} [3 x] - \ln (3 x) \frac{d}{d x} [x]}{x^{2}}$

Step 3.2.2

Rewrite the expression.

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

Step 3.3

Since $3$ is constant with respect to $x$ , the derivative of $3 x$ with respect to $x$ is $3 \frac{d}{d x} [x]$ .

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

Step 3.4

Simplify terms.

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Step 3.4.1

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

$\frac{\frac{3}{3} \frac{d}{d x} [x] - \ln (3 x) \frac{d}{d x} [x]}{x^{2}}$

Step 3.4.2

Cancel the common factor of $3$ .

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Step 3.4.2.1

Cancel the common factor.

$\frac{\frac{3}{3} \frac{d}{d x} [x] - \ln (3 x) \frac{d}{d x} [x]}{x^{2}}$

Step 3.4.2.2

Rewrite the expression.

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

Step 3.4.3

Multiply $\frac{d}{d x} [x]$ by $1$ .

$\frac{\frac{d}{d x} [x] - \ln (3 x) \frac{d}{d x} [x]}{x^{2}}$

Step 3.5

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 1$ .

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

Step 3.6

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 1$ .

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

Step 3.7

Multiply $- 1$ by $1$ .

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