Calculus Examples

$y = \frac{x^{3} + 1}{8 x}$

Step 1

Since $\frac{1}{8}$ is constant with respect to $x$ , the derivative of $\frac{x^{3} + 1}{8 x}$ with respect to $x$ is $\frac{1}{8} \frac{d}{d x} [\frac{x^{3} + 1}{x}]$ .

$\frac{1}{8} \frac{d}{d x} [\frac{x^{3} + 1}{x}]$

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

$\frac{1}{8} \cdot \frac{x \frac{d}{d x} [x^{3} + 1] - (x^{3} + 1) \frac{d}{d x} [x]}{x^{2}}$

Step 3

Differentiate.

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Step 3.1

By the Sum Rule, the derivative of $x^{3} + 1$ with respect to $x$ is $\frac{d}{d x} [x^{3}] + \frac{d}{d x} [1]$ .

$\frac{1}{8} \cdot \frac{x (\frac{d}{d x} [x^{3}] + \frac{d}{d x} [1]) - (x^{3} + 1) \frac{d}{d x} [x]}{x^{2}}$

Step 3.2

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

$\frac{1}{8} \cdot \frac{x (3 x^{2} + \frac{d}{d x} [1]) - (x^{3} + 1) \frac{d}{d x} [x]}{x^{2}}$

Step 3.3

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

$\frac{1}{8} \cdot \frac{x (3 x^{2} + 0) - (x^{3} + 1) \frac{d}{d x} [x]}{x^{2}}$

Step 3.4

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

$\frac{1}{8} \cdot \frac{x (3 x^{2}) - (x^{3} + 1) \frac{d}{d x} [x]}{x^{2}}$

Step 4

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

$\frac{1}{8} \cdot \frac{3 (x^{1} x^{2}) - (x^{3} + 1) \frac{d}{d x} [x]}{x^{2}}$

Step 5

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

$\frac{1}{8} \cdot \frac{3 x^{1 + 2} - (x^{3} + 1) \frac{d}{d x} [x]}{x^{2}}$

Step 6

Add $1$ and $2$ .

$\frac{1}{8} \cdot \frac{3 x^{3} - (x^{3} + 1) \frac{d}{d x} [x]}{x^{2}}$

Step 7

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

$\frac{1}{8} \cdot \frac{3 x^{3} - (x^{3} + 1) \cdot 1}{x^{2}}$

Step 8

Combine fractions.

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Step 8.1

Multiply $- 1$ by $1$ .

$\frac{1}{8} \cdot \frac{3 x^{3} - (x^{3} + 1)}{x^{2}}$

Step 8.2

Multiply $\frac{1}{8}$ by $\frac{3 x^{3} - (x^{3} + 1)}{x^{2}}$ .

$\frac{3 x^{3} - (x^{3} + 1)}{8 x^{2}}$

Step 9

Simplify.

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Step 9.1

Apply the distributive property.

$\frac{3 x^{3} - x^{3} - 1 \cdot 1}{8 x^{2}}$

Step 9.2

Simplify the numerator.

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Step 9.2.1

Multiply $- 1$ by $1$ .

$\frac{3 x^{3} - x^{3} - 1}{8 x^{2}}$

Step 9.2.2

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

$\frac{2 x^{3} - 1}{8 x^{2}}$