Algebra Examples

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

Step 1

Differentiate using the chain rule, which states that $\frac{d}{d x} [f (g (x))]$ is $f' (g (x)) g' (x)$ where $f (x) = \arctan (x)$ and $g (x) = \frac{2 x}{1 - x^{2}}$ .

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Step 1.1

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

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

Step 1.2

The derivative of $\arctan (u)$ with respect to $u$ is $\frac{1}{1 + u^{2}}$ .

$\frac{1}{1 + u^{2}} \frac{d}{d x} [\frac{2 x}{1 - x^{2}}]$

Step 1.3

Replace all occurrences of $u$ with $\frac{2 x}{1 - x^{2}}$ .

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

Step 2

Differentiate using the Constant Multiple Rule.

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Step 2.1

Since $2$ is constant with respect to $x$ , the derivative of $\frac{2 x}{1 - x^{2}}$ with respect to $x$ is $2 \frac{d}{d x} [\frac{x}{1 - x^{2}}]$ .

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

Step 2.2

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

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

Step 3

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 $f (x) = x$ and $g (x) = 1 - x^{2}$ .

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

Step 4

Differentiate.

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Step 4.1

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

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

Step 4.2

Multiply $1 - x^{2}$ by $1$ .

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

Step 4.3

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

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

Step 4.4

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

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

Step 4.5

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

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

Step 4.6

Since $- 1$ is constant with respect to $x$ , the derivative of $- x^{2}$ with respect to $x$ is $- \frac{d}{d x} [x^{2}]$ .

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

Step 4.7

Multiply.

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Step 4.7.1

Multiply $- 1$ by $- 1$ .

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

Step 4.7.2

Multiply $x$ by $1$ .

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

Step 4.8

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

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

Step 5

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

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

Step 6

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

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

Step 7

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

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

Step 8

Add $1$ and $1$ .

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

Step 9

Add $- x^{2}$ and $2 x^{2}$ .

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

Step 10

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

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

Step 11

Simplify.

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Step 11.1

Apply the product rule to $\frac{2 x}{1 - x^{2}}$ .

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

Step 11.2

Apply the product rule to $2 x$ .

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

Step 11.3

Apply the distributive property.

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

Step 11.4

Multiply $2$ by $1$ .

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

Step 11.5

Raise $2$ to the power of $2$ .

$\frac{2 + 2 x^{2}}{(1 + \frac{4 x^{2}}{{(1 - x^{2})}^{2}}) {(1 - x^{2})}^{2}}$

Step 11.6

Reorder terms.

$\frac{2 x^{2} + 2}{{(1 - x^{2})}^{2} (1 + \frac{4 x^{2}}{{(1 - x^{2})}^{2}})}$

Step 11.7

Simplify the denominator.

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Step 11.7.1

Rewrite $1$ as $1^{2}$ .

$\frac{2 x^{2} + 2}{{(1 - x^{2})}^{2} (1 + \frac{4 x^{2}}{{(1^{2} - x^{2})}^{2}})}$

Step 11.7.2

Since both terms are perfect squares, factor using the difference of squares formula, $a^{2} - b^{2} = (a + b) (a - b)$ where $a = 1$ and $b = x$ .

$\frac{2 x^{2} + 2}{{(1 - x^{2})}^{2} (1 + \frac{4 x^{2}}{{((1 + x) (1 - x))}^{2}})}$

Step 11.7.3

Apply the product rule to $(1 + x) (1 - x)$ .

$\frac{2 x^{2} + 2}{{(1 - x^{2})}^{2} (1 + \frac{4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}})}$

Step 11.8

Factor $2$ out of $2 x^{2} + 2$ .

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Step 11.8.1

Factor $2$ out of $2 x^{2}$ .

$\frac{2 (x^{2}) + 2}{{(1 - x^{2})}^{2} (1 + \frac{4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}})}$

Step 11.8.2

Factor $2$ out of $2$ .

$\frac{2 (x^{2}) + 2 (1)}{{(1 - x^{2})}^{2} (1 + \frac{4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}})}$

Step 11.8.3

Factor $2$ out of $2 (x^{2}) + 2 (1)$ .

$\frac{2 (x^{2} + 1)}{{(1 - x^{2})}^{2} (1 + \frac{4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}})}$

Step 11.9

Simplify the denominator.

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Step 11.9.1

Rewrite $1$ as $1^{2}$ .

$\frac{2 (x^{2} + 1)}{{(1^{2} - x^{2})}^{2} (1 + \frac{4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}})}$

Step 11.9.2

Since both terms are perfect squares, factor using the difference of squares formula, $a^{2} - b^{2} = (a + b) (a - b)$ where $a = 1$ and $b = x$ .

$\frac{2 (x^{2} + 1)}{{((1 + x) (1 - x))}^{2} (1 + \frac{4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}})}$

Step 11.9.3

Apply the product rule to $(1 + x) (1 - x)$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} (1 + \frac{4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}})}$

Step 11.9.4

Write $1$ as a fraction with a common denominator.

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} (\frac{{(1 + x)}^{2} {(1 - x)}^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}} + \frac{4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}})}$

Step 11.9.5

Combine the numerators over the common denominator.

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{{(1 + x)}^{2} {(1 - x)}^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6

Simplify the numerator.

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Step 11.9.6.1

Rewrite ${(1 + x)}^{2}$ as $(1 + x) (1 + x)$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + x) (1 + x) {(1 - x)}^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.2

Expand $(1 + x) (1 + x)$ using the FOIL Method.

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Step 11.9.6.2.1

Apply the distributive property.

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 (1 + x) + x (1 + x)) {(1 - x)}^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.2.2

Apply the distributive property.

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 \cdot 1 + 1 x + x (1 + x)) {(1 - x)}^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.2.3

Apply the distributive property.

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 \cdot 1 + 1 x + x \cdot 1 + x \cdot x) {(1 - x)}^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.3

Simplify and combine like terms.

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Step 11.9.6.3.1

Simplify each term.

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Step 11.9.6.3.1.1

Multiply $1$ by $1$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 1 x + x \cdot 1 + x \cdot x) {(1 - x)}^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.3.1.2

Multiply $x$ by $1$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + x + x \cdot 1 + x \cdot x) {(1 - x)}^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.3.1.3

Multiply $x$ by $1$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + x + x + x \cdot x) {(1 - x)}^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.3.1.4

Multiply $x$ by $x$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + x + x + x^{2}) {(1 - x)}^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.3.2

Add $x$ and $x$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) {(1 - x)}^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.4

Rewrite ${(1 - x)}^{2}$ as $(1 - x) (1 - x)$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) ((1 - x) (1 - x)) + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.5

Expand $(1 - x) (1 - x)$ using the FOIL Method.

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Step 11.9.6.5.1

Apply the distributive property.

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) (1 (1 - x) - x (1 - x)) + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.5.2

Apply the distributive property.

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) (1 \cdot 1 + 1 (- x) - x (1 - x)) + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.5.3

Apply the distributive property.

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) (1 \cdot 1 + 1 (- x) - x \cdot 1 - x (- x)) + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.6

Simplify and combine like terms.

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Step 11.9.6.6.1

Simplify each term.

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Step 11.9.6.6.1.1

Multiply $1$ by $1$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) (1 + 1 (- x) - x \cdot 1 - x (- x)) + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.6.1.2

Multiply $- x$ by $1$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) (1 - x - x \cdot 1 - x (- x)) + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.6.1.3

Multiply $- 1$ by $1$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) (1 - x - x - x (- x)) + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.6.1.4

Rewrite using the commutative property of multiplication.

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) (1 - x - x - 1 \cdot - 1 x \cdot x) + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.6.1.5

Multiply $x$ by $x$ by adding the exponents.

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Step 11.9.6.6.1.5.1

Move $x$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) (1 - x - x - 1 \cdot - 1 (x \cdot x)) + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.6.1.5.2

Multiply $x$ by $x$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) (1 - x - x - 1 \cdot - 1 x^{2}) + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.6.1.6

Multiply $- 1$ by $- 1$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) (1 - x - x + 1 x^{2}) + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.6.1.7

Multiply $x^{2}$ by $1$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) (1 - x - x + x^{2}) + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.6.2

Subtract $x$ from $- x$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{(1 + 2 x + x^{2}) (1 - 2 x + x^{2}) + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.7

Expand $(1 + 2 x + x^{2}) (1 - 2 x + x^{2})$ by multiplying each term in the first expression by each term in the second expression.

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 \cdot 1 + 1 (- 2 x) + 1 x^{2} + 2 x \cdot 1 + 2 x (- 2 x) + 2 x \cdot x^{2} + x^{2} \cdot 1 + x^{2} (- 2 x) + x^{2} x^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.8

Combine the opposite terms in $1 \cdot 1 + 1 (- 2 x) + 1 x^{2} + 2 x \cdot 1 + 2 x (- 2 x) + 2 x \cdot x^{2} + x^{2} \cdot 1 + x^{2} (- 2 x) + x^{2} x^{2}$ .

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Step 11.9.6.8.1

Reorder the factors in the terms $2 x \cdot x^{2}$ and $x^{2} (- 2 x)$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 \cdot 1 + 1 (- 2 x) + 1 x^{2} + 2 x \cdot 1 + 2 x (- 2 x) + 2 x^{2} x + x^{2} \cdot 1 - 2 x^{2} x + x^{2} x^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.8.2

Subtract $2 x^{2} x$ from $2 x^{2} x$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 \cdot 1 + 1 (- 2 x) + 1 x^{2} + 2 x \cdot 1 + 2 x (- 2 x) + x^{2} \cdot 1 + 0 + x^{2} x^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.8.3

Add $1 \cdot 1 + 1 (- 2 x) + 1 x^{2} + 2 x \cdot 1 + 2 x (- 2 x) + x^{2} \cdot 1$ and $0$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 \cdot 1 + 1 (- 2 x) + 1 x^{2} + 2 x \cdot 1 + 2 x (- 2 x) + x^{2} \cdot 1 + x^{2} x^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.9

Simplify each term.

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Step 11.9.6.9.1

Multiply $1$ by $1$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 + 1 (- 2 x) + 1 x^{2} + 2 x \cdot 1 + 2 x (- 2 x) + x^{2} \cdot 1 + x^{2} x^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.9.2

Multiply $- 2 x$ by $1$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 - 2 x + 1 x^{2} + 2 x \cdot 1 + 2 x (- 2 x) + x^{2} \cdot 1 + x^{2} x^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.9.3

Multiply $x^{2}$ by $1$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 - 2 x + x^{2} + 2 x \cdot 1 + 2 x (- 2 x) + x^{2} \cdot 1 + x^{2} x^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.9.4

Multiply $2$ by $1$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 - 2 x + x^{2} + 2 x + 2 x (- 2 x) + x^{2} \cdot 1 + x^{2} x^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.9.5

Rewrite using the commutative property of multiplication.

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 - 2 x + x^{2} + 2 x + 2 \cdot - 2 x \cdot x + x^{2} \cdot 1 + x^{2} x^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.9.6

Multiply $x$ by $x$ by adding the exponents.

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Step 11.9.6.9.6.1

Move $x$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 - 2 x + x^{2} + 2 x + 2 \cdot - 2 (x \cdot x) + x^{2} \cdot 1 + x^{2} x^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.9.6.2

Multiply $x$ by $x$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 - 2 x + x^{2} + 2 x + 2 \cdot - 2 x^{2} + x^{2} \cdot 1 + x^{2} x^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.9.7

Multiply $2$ by $- 2$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 - 2 x + x^{2} + 2 x - 4 x^{2} + x^{2} \cdot 1 + x^{2} x^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.9.8

Multiply $x^{2}$ by $1$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 - 2 x + x^{2} + 2 x - 4 x^{2} + x^{2} + x^{2} x^{2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.9.9

Multiply $x^{2}$ by $x^{2}$ by adding the exponents.

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Step 11.9.6.9.9.1

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

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 - 2 x + x^{2} + 2 x - 4 x^{2} + x^{2} + x^{2 + 2} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.9.9.2

Add $2$ and $2$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 - 2 x + x^{2} + 2 x - 4 x^{2} + x^{2} + x^{4} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.10

Combine the opposite terms in $1 - 2 x + x^{2} + 2 x - 4 x^{2} + x^{2} + x^{4}$ .

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Step 11.9.6.10.1

Add $- 2 x$ and $2 x$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 + x^{2} + 0 - 4 x^{2} + x^{2} + x^{4} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.10.2

Add $1 + x^{2}$ and $0$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 + x^{2} - 4 x^{2} + x^{2} + x^{4} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.11

Subtract $4 x^{2}$ from $x^{2}$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 - 3 x^{2} + x^{2} + x^{4} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.12

Add $- 3 x^{2}$ and $x^{2}$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 - 2 x^{2} + x^{4} + 4 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.13

Add $- 2 x^{2}$ and $4 x^{2}$ .

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{1 + x^{4} + 2 x^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.14

Reorder terms.

$\frac{2 (x^{2} + 1)}{{(1 + x)}^{2} {(1 - x)}^{2} \frac{x^{4} + 2 x^{2} + 1}{{(1 + x)}^{2} {(1 - x)}^{2}}}$

Step 11.9.6.15

Rewrite $x^{4} + 2 x^{2} + 1$ in a factored form.

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Step 11.9.6.15.1

Rewrite $x^{4}$ as ${(x^{2})}^{2}$ .

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

Step 11.9.6.15.2

Let $u = x^{2}$ . Substitute $u$ for all occurrences of $x^{2}$ .

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

Step 11.9.6.15.3

Factor using the perfect square rule.

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Step 11.9.6.15.3.1

Rewrite $1$ as $1^{2}$ .

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

Step 11.9.6.15.3.2

Check that the middle term is two times the product of the numbers being squared in the first term and third term.

$2 u = 2 \cdot u \cdot 1$

Step 11.9.6.15.3.3

Rewrite the polynomial.

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

Step 11.9.6.15.3.4

Factor using the perfect square trinomial rule $a^{2} + 2 a b + b^{2} = {(a + b)}^{2}$ , where $a = u$ and $b = 1$ .

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

Step 11.9.6.15.4

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

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

Step 11.9.7

Combine exponents.

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Step 11.9.7.1

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

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

Step 11.9.7.2

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

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

Step 11.9.8

Reduce the expression $\frac{{(x^{2} + 1)}^{2} {(1 + x)}^{2} {(1 - x)}^{2}}{{(1 + x)}^{2} {(1 - x)}^{2}}$ by cancelling the common factors.

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Step 11.9.8.1

Cancel the common factor.

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

Step 11.9.8.2

Rewrite the expression.

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

Step 11.9.9

Cancel the common factor of ${(1 - x)}^{2}$ .

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Step 11.9.9.1

Cancel the common factor.

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

Step 11.9.9.2

Divide ${(x^{2} + 1)}^{2}$ by $1$ .

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

Step 11.9.10

Rewrite ${(x^{2} + 1)}^{2}$ as $(x^{2} + 1) (x^{2} + 1)$ .

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

Step 11.9.11

Expand $(x^{2} + 1) (x^{2} + 1)$ using the FOIL Method.

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Step 11.9.11.1

Apply the distributive property.

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

Step 11.9.11.2

Apply the distributive property.

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

Step 11.9.11.3

Apply the distributive property.

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

Step 11.9.12

Simplify and combine like terms.

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Step 11.9.12.1

Simplify each term.

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Step 11.9.12.1.1

Multiply $x^{2}$ by $x^{2}$ by adding the exponents.

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Step 11.9.12.1.1.1

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

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

Step 11.9.12.1.1.2

Add $2$ and $2$ .

$\frac{2 (x^{2} + 1)}{x^{4} + x^{2} \cdot 1 + 1 x^{2} + 1 \cdot 1}$

Step 11.9.12.1.2

Multiply $x^{2}$ by $1$ .

$\frac{2 (x^{2} + 1)}{x^{4} + x^{2} + 1 x^{2} + 1 \cdot 1}$

Step 11.9.12.1.3

Multiply $x^{2}$ by $1$ .

$\frac{2 (x^{2} + 1)}{x^{4} + x^{2} + x^{2} + 1 \cdot 1}$

Step 11.9.12.1.4

Multiply $1$ by $1$ .

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

Step 11.9.12.2

Add $x^{2}$ and $x^{2}$ .

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

Step 11.9.13

Rewrite $x^{4}$ as ${(x^{2})}^{2}$ .

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

Step 11.9.14

Let $u = x^{2}$ . Substitute $u$ for all occurrences of $x^{2}$ .

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

Step 11.9.15

Factor using the perfect square rule.

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Step 11.9.15.1

Rewrite $1$ as $1^{2}$ .

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

Step 11.9.15.2

Check that the middle term is two times the product of the numbers being squared in the first term and third term.

$2 u = 2 \cdot u \cdot 1$

Step 11.9.15.3

Rewrite the polynomial.

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

Step 11.9.15.4

Factor using the perfect square trinomial rule $a^{2} + 2 a b + b^{2} = {(a + b)}^{2}$ , where $a = u$ and $b = 1$ .

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

Step 11.9.16

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

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

Step 11.10

Cancel the common factor of $x^{2} + 1$ and ${(x^{2} + 1)}^{2}$ .

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Step 11.10.1

Factor $x^{2} + 1$ out of $2 (x^{2} + 1)$ .

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

Step 11.10.2

Cancel the common factors.

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Step 11.10.2.1

Factor $x^{2} + 1$ out of ${(x^{2} + 1)}^{2}$ .

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

Step 11.10.2.2

Cancel the common factor.

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

Step 11.10.2.3

Rewrite the expression.

$\frac{2}{x^{2} + 1}$