Calculus Examples

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

Step 1

By the Sum Rule, the derivative of $\frac{1}{x^{3}} - \frac{1}{x} + x^{2}$ with respect to $x$ is $\frac{d}{d x} [\frac{1}{x^{3}}] + \frac{d}{d x} [- \frac{1}{x}] + \frac{d}{d x} [x^{2}]$ .

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

Step 2

Evaluate $\frac{d}{d x} [\frac{1}{x^{3}}]$ .

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Step 2.1

Rewrite $\frac{1}{x^{3}}$ as ${(x^{3})}^{- 1}$ .

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

Step 2.2

Differentiate using the chain rule, which states that $\frac{d}{d x} [f (g (x))]$ is $f' (g (x)) g' (x)$ where $f (x) = x^{- 1}$ and $g (x) = x^{3}$ .

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Step 2.2.1

To apply the Chain Rule, set $u$ as $x^{3}$ .

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

Step 2.2.2

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

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

Step 2.2.3

Replace all occurrences of $u$ with $x^{3}$ .

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

Step 2.3

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

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

Step 2.4

Multiply the exponents in ${(x^{3})}^{- 2}$ .

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Step 2.4.1

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

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

Step 2.4.2

Multiply $3$ by $- 2$ .

$- x^{- 6} (3 x^{2}) + \frac{d}{d x} [- \frac{1}{x}] + \frac{d}{d x} [x^{2}]$

Step 2.5

Multiply $3$ by $- 1$ .

$- 3 x^{- 6} x^{2} + \frac{d}{d x} [- \frac{1}{x}] + \frac{d}{d x} [x^{2}]$

Step 2.6

Multiply $x^{- 6}$ by $x^{2}$ by adding the exponents.

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Step 2.6.1

Move $x^{2}$ .

$- 3 (x^{2} x^{- 6}) + \frac{d}{d x} [- \frac{1}{x}] + \frac{d}{d x} [x^{2}]$

Step 2.6.2

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

$- 3 x^{2 - 6} + \frac{d}{d x} [- \frac{1}{x}] + \frac{d}{d x} [x^{2}]$

Step 2.6.3

Subtract $6$ from $2$ .

$- 3 x^{- 4} + \frac{d}{d x} [- \frac{1}{x}] + \frac{d}{d x} [x^{2}]$

Step 3

Evaluate $\frac{d}{d x} [- \frac{1}{x}]$ .

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Step 3.1

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 $f (x) = - 1$ and $g (x) = \frac{1}{x}$ .

$- 3 x^{- 4} - \frac{d}{d x} [\frac{1}{x}] + \frac{1}{x} \frac{d}{d x} [- 1] + \frac{d}{d x} [x^{2}]$

Step 3.2

Rewrite $\frac{1}{x}$ as $x^{- 1}$ .

$- 3 x^{- 4} - \frac{d}{d x} [x^{- 1}] + \frac{1}{x} \frac{d}{d x} [- 1] + \frac{d}{d x} [x^{2}]$

Step 3.3

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

$- 3 x^{- 4} - - x^{- 2} + \frac{1}{x} \frac{d}{d x} [- 1] + \frac{d}{d x} [x^{2}]$

Step 3.4

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

$- 3 x^{- 4} - - x^{- 2} + \frac{1}{x} \cdot 0 + \frac{d}{d x} [x^{2}]$

Step 3.5

Multiply $- 1$ by $- 1$ .

$- 3 x^{- 4} + 1 x^{- 2} + \frac{1}{x} \cdot 0 + \frac{d}{d x} [x^{2}]$

Step 3.6

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

$- 3 x^{- 4} + x^{- 2} + \frac{1}{x} \cdot 0 + \frac{d}{d x} [x^{2}]$

Step 3.7

Multiply $\frac{1}{x}$ by $0$ .

$- 3 x^{- 4} + x^{- 2} + 0 + \frac{d}{d x} [x^{2}]$

Step 3.8

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

$- 3 x^{- 4} + x^{- 2} + \frac{d}{d x} [x^{2}]$

Step 4

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

$- 3 x^{- 4} + x^{- 2} + 2 x$

Step 5

Simplify.

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Step 5.1

Rewrite the expression using the negative exponent rule $b^{- n} = \frac{1}{b^{n}}$ .

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

Step 5.2

Rewrite the expression using the negative exponent rule $b^{- n} = \frac{1}{b^{n}}$ .

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

Step 5.3

Combine terms.

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Step 5.3.1

Combine $- 3$ and $\frac{1}{x^{4}}$ .

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

Step 5.3.2

Move the negative in front of the fraction.

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

Step 5.4

Reorder terms.

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