Calculus Examples

$\frac{120 x^{2}}{x^{2} + 4}$

Step 1

Since $120$ is constant with respect to $x$ , the derivative of $\frac{120 x^{2}}{x^{2} + 4}$ with respect to $x$ is $120 \frac{d}{d x} [\frac{x^{2}}{x^{2} + 4}]$ .

$120 \frac{d}{d x} [\frac{x^{2}}{x^{2} + 4}]$

Step 2

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 $f (x) = x^{2}$ and $g (x) = x^{2} + 4$ .

$120 \frac{(x^{2} + 4) \frac{d}{d x} [x^{2}] - x^{2} \frac{d}{d x} [x^{2} + 4]}{{(x^{2} + 4)}^{2}}$

Step 3

Differentiate.

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Step 3.1

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

$120 \frac{(x^{2} + 4) (2 x) - x^{2} \frac{d}{d x} [x^{2} + 4]}{{(x^{2} + 4)}^{2}}$

Step 3.2

Move $2$ to the left of $x^{2} + 4$ .

$120 \frac{2 \cdot (x^{2} + 4) x - x^{2} \frac{d}{d x} [x^{2} + 4]}{{(x^{2} + 4)}^{2}}$

Step 3.3

By the Sum Rule, the derivative of $x^{2} + 4$ with respect to $x$ is $\frac{d}{d x} [x^{2}] + \frac{d}{d x} [4]$ .

$120 \frac{2 (x^{2} + 4) x - x^{2} (\frac{d}{d x} [x^{2}] + \frac{d}{d x} [4])}{{(x^{2} + 4)}^{2}}$

Step 3.4

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

$120 \frac{2 (x^{2} + 4) x - x^{2} (2 x + \frac{d}{d x} [4])}{{(x^{2} + 4)}^{2}}$

Step 3.5

Since $4$ is constant with respect to $x$ , the derivative of $4$ with respect to $x$ is $0$ .

$120 \frac{2 (x^{2} + 4) x - x^{2} (2 x + 0)}{{(x^{2} + 4)}^{2}}$

Step 3.6

Simplify the expression.

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Step 3.6.1

Add $2 x$ and $0$ .

$120 \frac{2 (x^{2} + 4) x - x^{2} (2 x)}{{(x^{2} + 4)}^{2}}$

Step 3.6.2

Multiply $2$ by $- 1$ .

$120 \frac{2 (x^{2} + 4) x - 2 x^{2} x}{{(x^{2} + 4)}^{2}}$

Step 4

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

$120 \frac{2 (x^{2} + 4) x - 2 (x^{1} x^{2})}{{(x^{2} + 4)}^{2}}$

Step 5

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

$120 \frac{2 (x^{2} + 4) x - 2 x^{1 + 2}}{{(x^{2} + 4)}^{2}}$

Step 6

Add $1$ and $2$ .

$120 \frac{2 (x^{2} + 4) x - 2 x^{3}}{{(x^{2} + 4)}^{2}}$

Step 7

Combine $120$ and $\frac{2 (x^{2} + 4) x - 2 x^{3}}{{(x^{2} + 4)}^{2}}$ .

$\frac{120 (2 (x^{2} + 4) x - 2 x^{3})}{{(x^{2} + 4)}^{2}}$

Step 8

Simplify.

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Step 8.1

Apply the distributive property.

$\frac{120 ((2 x^{2} + 2 \cdot 4) x - 2 x^{3})}{{(x^{2} + 4)}^{2}}$

Step 8.2

Apply the distributive property.

$\frac{120 (2 x^{2} x + 2 \cdot 4 x - 2 x^{3})}{{(x^{2} + 4)}^{2}}$

Step 8.3

Apply the distributive property.

$\frac{120 (2 x^{2} x) + 120 (2 \cdot 4 x) + 120 (- 2 x^{3})}{{(x^{2} + 4)}^{2}}$

Step 8.4

Simplify the numerator.

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Step 8.4.1

Simplify each term.

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Step 8.4.1.1

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

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Step 8.4.1.1.1

Move $x$ .

$\frac{120 (2 (x \cdot x^{2})) + 120 (2 \cdot 4 x) + 120 (- 2 x^{3})}{{(x^{2} + 4)}^{2}}$

Step 8.4.1.1.2

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

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Step 8.4.1.1.2.1

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

$\frac{120 (2 (x^{1} x^{2})) + 120 (2 \cdot 4 x) + 120 (- 2 x^{3})}{{(x^{2} + 4)}^{2}}$

Step 8.4.1.1.2.2

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

$\frac{120 (2 x^{1 + 2}) + 120 (2 \cdot 4 x) + 120 (- 2 x^{3})}{{(x^{2} + 4)}^{2}}$

Step 8.4.1.1.3

Add $1$ and $2$ .

$\frac{120 (2 x^{3}) + 120 (2 \cdot 4 x) + 120 (- 2 x^{3})}{{(x^{2} + 4)}^{2}}$

Step 8.4.1.2

Multiply $2$ by $120$ .

$\frac{240 x^{3} + 120 (2 \cdot 4 x) + 120 (- 2 x^{3})}{{(x^{2} + 4)}^{2}}$

Step 8.4.1.3

Multiply $2$ by $4$ .

$\frac{240 x^{3} + 120 (8 x) + 120 (- 2 x^{3})}{{(x^{2} + 4)}^{2}}$

Step 8.4.1.4

Multiply $8$ by $120$ .

$\frac{240 x^{3} + 960 x + 120 (- 2 x^{3})}{{(x^{2} + 4)}^{2}}$

Step 8.4.1.5

Multiply $- 2$ by $120$ .

$\frac{240 x^{3} + 960 x - 240 x^{3}}{{(x^{2} + 4)}^{2}}$

Step 8.4.2

Combine the opposite terms in $240 x^{3} + 960 x - 240 x^{3}$ .

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Step 8.4.2.1

Subtract $240 x^{3}$ from $240 x^{3}$ .

$\frac{960 x + 0}{{(x^{2} + 4)}^{2}}$

Step 8.4.2.2

Add $960 x$ and $0$ .

$\frac{960 x}{{(x^{2} + 4)}^{2}}$