Calculus Examples

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

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 $f (x) = x^{3} + 3 x + 2$ and $g (x) = x^{2} - 1$ .

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

Step 2

Differentiate.

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Step 2.1

By the Sum Rule, the derivative of $x^{3} + 3 x + 2$ with respect to $x$ is $\frac{d}{d x} [x^{3}] + \frac{d}{d x} [3 x] + \frac{d}{d x} [2]$ .

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

Step 2.2

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 3$ .

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

Step 3

Evaluate $\frac{d}{d x} [3 x]$ .

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Step 3.1

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

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

Step 3.2

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

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

Step 3.3

Multiply $3$ by $1$ .

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

Step 4

Differentiate.

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Step 4.1

Since $2$ is constant with respect to $x$ , the derivative of $2$ with respect to $x$ is $0$ .

$\frac{(x^{2} - 1) (3 x^{2} + 3 + 0) - (x^{3} + 3 x + 2) \frac{d}{d x} [x^{2} - 1]}{{(x^{2} - 1)}^{2}}$

Step 4.2

Add $3 x^{2} + 3$ and $0$ .

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

Step 4.3

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

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

Step 4.4

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

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

Step 4.5

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

$\frac{(x^{2} - 1) (3 x^{2} + 3) - (x^{3} + 3 x + 2) (2 x + 0)}{{(x^{2} - 1)}^{2}}$

Step 4.6

Add $2 x$ and $0$ .

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

Step 5

Simplify.

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Step 5.1

Apply the distributive property.

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

Step 5.2

Apply the distributive property.

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

Step 5.3

Simplify the numerator.

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Step 5.3.1

Simplify each term.

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Step 5.3.1.1

Expand $(x^{2} - 1) (3 x^{2} + 3)$ using the FOIL Method.

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Step 5.3.1.1.1

Apply the distributive property.

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

Step 5.3.1.1.2

Apply the distributive property.

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

Step 5.3.1.1.3

Apply the distributive property.

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

Step 5.3.1.2

Simplify and combine like terms.

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Step 5.3.1.2.1

Simplify each term.

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Step 5.3.1.2.1.1

Rewrite using the commutative property of multiplication.

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

Step 5.3.1.2.1.2

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

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Step 5.3.1.2.1.2.1

Move $x^{2}$ .

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

Step 5.3.1.2.1.2.2

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

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

Step 5.3.1.2.1.2.3

Add $2$ and $2$ .

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

Step 5.3.1.2.1.3

Move $3$ to the left of $x^{2}$ .

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

Step 5.3.1.2.1.4

Multiply $3$ by $- 1$ .

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

Step 5.3.1.2.1.5

Multiply $- 1$ by $3$ .

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

Step 5.3.1.2.2

Subtract $3 x^{2}$ from $3 x^{2}$ .

$\frac{3 x^{4} + 0 - 3 - x^{3} (2 x) - (3 x) (2 x) - 1 \cdot 2 (2 x)}{{(x^{2} - 1)}^{2}}$

Step 5.3.1.2.3

Add $3 x^{4}$ and $0$ .

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

Step 5.3.1.3

Rewrite using the commutative property of multiplication.

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

Step 5.3.1.4

Multiply $x^{3}$ by $x$ by adding the exponents.

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Step 5.3.1.4.1

Move $x$ .

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

Step 5.3.1.4.2

Multiply $x$ by $x^{3}$ .

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Step 5.3.1.4.2.1

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

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

Step 5.3.1.4.2.2

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

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

Step 5.3.1.4.3

Add $1$ and $3$ .

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

Step 5.3.1.5

Multiply $- 1$ by $2$ .

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

Step 5.3.1.6

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

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Step 5.3.1.6.1

Move $x$ .

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

Step 5.3.1.6.2

Multiply $x$ by $x$ .

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

Step 5.3.1.7

Multiply $3$ by $- 1$ .

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

Step 5.3.1.8

Multiply $2$ by $- 3$ .

$\frac{3 x^{4} - 3 - 2 x^{4} - 6 x^{2} - 1 \cdot 2 (2 x)}{{(x^{2} - 1)}^{2}}$

Step 5.3.1.9

Multiply $- 1$ by $2$ .

$\frac{3 x^{4} - 3 - 2 x^{4} - 6 x^{2} - 2 (2 x)}{{(x^{2} - 1)}^{2}}$

Step 5.3.1.10

Multiply $2$ by $- 2$ .

$\frac{3 x^{4} - 3 - 2 x^{4} - 6 x^{2} - 4 x}{{(x^{2} - 1)}^{2}}$

Step 5.3.2

Subtract $2 x^{4}$ from $3 x^{4}$ .

$\frac{x^{4} - 3 - 6 x^{2} - 4 x}{{(x^{2} - 1)}^{2}}$

Step 5.4

Reorder terms.

$\frac{x^{4} - 6 x^{2} - 4 x - 3}{{(x^{2} - 1)}^{2}}$

Step 5.5

Simplify the denominator.

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Step 5.5.1

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

$\frac{x^{4} - 6 x^{2} - 4 x - 3}{{(x^{2} - 1^{2})}^{2}}$

Step 5.5.2

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

$\frac{x^{4} - 6 x^{2} - 4 x - 3}{{((x + 1) (x - 1))}^{2}}$

Step 5.5.3

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

$\frac{x^{4} - 6 x^{2} - 4 x - 3}{{(x + 1)}^{2} {(x - 1)}^{2}}$