Calculus Examples

$f (x) = x \ln (1 + x^{2})$

Step 1

Differentiate using the Product Rule which states that $\frac{d}{d x} [f (x) g (x)]$ is $f (x) \frac{d}{d x} [g (x)] + g (x) \frac{d}{d x} [f (x)]$ where $f (x) = x$ and $g (x) = \ln (1 + x^{2})$ .

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

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 $g (x) = 1 + x^{2}$ .

Tap for more steps...

Step 2.1

To apply the Chain Rule, set $u$ as $1 + x^{2}$ .

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

Step 2.2

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

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

Step 2.3

Replace all occurrences of $u$ with $1 + x^{2}$ .

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

Step 3

Differentiate.

Tap for more steps...

Step 3.1

Combine $\frac{1}{1 + x^{2}}$ and $x$ .

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

Step 3.2

By the Sum Rule, the derivative of $1 + x^{2}$ with respect to $x$ is $\frac{d}{d x} [1] + \frac{d}{d x} [x^{2}]$ .

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

Step 3.3

Since $1$ is constant with respect to $x$ , the derivative of $1$ with respect to $x$ is $0$ .

$\frac{x}{1 + x^{2}} (0 + \frac{d}{d x} [x^{2}]) + \ln (1 + x^{2}) \frac{d}{d x} [x]$

Step 3.4

Add $0$ and $\frac{d}{d x} [x^{2}]$ .

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

Step 3.5

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 2$ .

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

Step 3.6

Combine fractions.

Tap for more steps...

Step 3.6.1

Combine $2$ and $\frac{x}{1 + x^{2}}$ .

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

Step 3.6.2

Combine $\frac{2 x}{1 + x^{2}}$ and $x$ .

$\frac{2 x \cdot x}{1 + x^{2}} + \ln (1 + x^{2}) \frac{d}{d x} [x]$

Step 4

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

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

Step 5

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

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

Step 6

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

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

Step 7

Add $1$ and $1$ .

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

Step 8

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

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

Step 9

Multiply $\ln (1 + x^{2})$ by $1$ .

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

Step 10

To write $\ln (1 + x^{2})$ as a fraction with a common denominator, multiply by $\frac{1 + x^{2}}{1 + x^{2}}$ .

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

Step 11

Combine the numerators over the common denominator.

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

Step 12

Simplify.

Tap for more steps...

Step 12.1

Simplify the numerator.

Tap for more steps...

Step 12.1.1

Simplify each term.

Tap for more steps...

Step 12.1.1.1

Apply the distributive property.

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

Step 12.1.1.2

Multiply $\ln (1 + x^{2})$ by $1$ .

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

Step 12.1.2

Reorder factors in $2 x^{2} + \ln (1 + x^{2}) + \ln (1 + x^{2}) x^{2}$ .

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

Step 12.2

Reorder terms.

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