Calculus Examples

$y = \frac{9 + 8 x - 4 \sqrt{x}}{x}$

Step 1

Use $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$ to rewrite $\sqrt{x}$ as $x^{\frac{1}{2}}$ .

$\frac{d}{d x} [\frac{9 + 8 x - 4 x^{\frac{1}{2}}}{x}]$

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 $f (x) = 9 + 8 x - 4 x^{\frac{1}{2}}$ and $g (x) = x$ .

$\frac{x \frac{d}{d x} [9 + 8 x - 4 x^{\frac{1}{2}}] - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 3

Differentiate.

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Step 3.1

By the Sum Rule, the derivative of $9 + 8 x - 4 x^{\frac{1}{2}}$ with respect to $x$ is $\frac{d}{d x} [9] + \frac{d}{d x} [8 x] + \frac{d}{d x} [- 4 x^{\frac{1}{2}}]$ .

$\frac{x (\frac{d}{d x} [9] + \frac{d}{d x} [8 x] + \frac{d}{d x} [- 4 x^{\frac{1}{2}}]) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 3.2

Since $9$ is constant with respect to $x$ , the derivative of $9$ with respect to $x$ is $0$ .

$\frac{x (0 + \frac{d}{d x} [8 x] + \frac{d}{d x} [- 4 x^{\frac{1}{2}}]) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 3.3

Add $0$ and $\frac{d}{d x} [8 x]$ .

$\frac{x (\frac{d}{d x} [8 x] + \frac{d}{d x} [- 4 x^{\frac{1}{2}}]) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 3.4

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

$\frac{x (8 \frac{d}{d x} [x] + \frac{d}{d x} [- 4 x^{\frac{1}{2}}]) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 3.5

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

$\frac{x (8 \cdot 1 + \frac{d}{d x} [- 4 x^{\frac{1}{2}}]) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 3.6

Multiply $8$ by $1$ .

$\frac{x (8 + \frac{d}{d x} [- 4 x^{\frac{1}{2}}]) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 3.7

Since $- 4$ is constant with respect to $x$ , the derivative of $- 4 x^{\frac{1}{2}}$ with respect to $x$ is $- 4 \frac{d}{d x} [x^{\frac{1}{2}}]$ .

$\frac{x (8 - 4 \frac{d}{d x} [x^{\frac{1}{2}}]) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 3.8

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

$\frac{x (8 - 4 (\frac{1}{2} x^{\frac{1}{2} - 1})) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 4

To write $- 1$ as a fraction with a common denominator, multiply by $\frac{2}{2}$ .

$\frac{x (8 - 4 (\frac{1}{2} x^{\frac{1}{2} - 1 \cdot \frac{2}{2}})) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 5

Combine $- 1$ and $\frac{2}{2}$ .

$\frac{x (8 - 4 (\frac{1}{2} x^{\frac{1}{2} + \frac{- 1 \cdot 2}{2}})) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 6

Combine the numerators over the common denominator.

$\frac{x (8 - 4 (\frac{1}{2} x^{\frac{1 - 1 \cdot 2}{2}})) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 7

Simplify the numerator.

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Step 7.1

Multiply $- 1$ by $2$ .

$\frac{x (8 - 4 (\frac{1}{2} x^{\frac{1 - 2}{2}})) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 7.2

Subtract $2$ from $1$ .

$\frac{x (8 - 4 (\frac{1}{2} x^{\frac{- 1}{2}})) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 8

Move the negative in front of the fraction.

$\frac{x (8 - 4 (\frac{1}{2} x^{- \frac{1}{2}})) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 9

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

$\frac{x (8 - 4 \frac{x^{- \frac{1}{2}}}{2}) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 10

Combine $- 4$ and $\frac{x^{- \frac{1}{2}}}{2}$ .

$\frac{x (8 + \frac{- 4 x^{- \frac{1}{2}}}{2}) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 11

Move $x^{- \frac{1}{2}}$ to the denominator using the negative exponent rule $b^{- n} = \frac{1}{b^{n}}$ .

$\frac{x (8 + \frac{- 4}{2 x^{\frac{1}{2}}}) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 12

Factor $2$ out of $- 4$ .

$\frac{x (8 + \frac{2 \cdot - 2}{2 x^{\frac{1}{2}}}) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 13

Cancel the common factors.

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Step 13.1

Factor $2$ out of $2 x^{\frac{1}{2}}$ .

$\frac{x (8 + \frac{2 \cdot - 2}{2 (x^{\frac{1}{2}})}) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 13.2

Cancel the common factor.

$\frac{x (8 + \frac{2 \cdot - 2}{2 x^{\frac{1}{2}}}) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 13.3

Rewrite the expression.

$\frac{x (8 + \frac{- 2}{x^{\frac{1}{2}}}) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 14

Move the negative in front of the fraction.

$\frac{x (8 - \frac{2}{x^{\frac{1}{2}}}) - (9 + 8 x - 4 x^{\frac{1}{2}}) \frac{d}{d x} [x]}{x^{2}}$

Step 15

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

$\frac{x (8 - \frac{2}{x^{\frac{1}{2}}}) - (9 + 8 x - 4 x^{\frac{1}{2}}) \cdot 1}{x^{2}}$

Step 16

Multiply $- 1$ by $1$ .

$\frac{x (8 - \frac{2}{x^{\frac{1}{2}}}) - (9 + 8 x - 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17

Simplify.

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Step 17.1

Apply the distributive property.

$\frac{x \cdot 8 + x (- \frac{2}{x^{\frac{1}{2}}}) - (9 + 8 x - 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.2

Apply the distributive property.

$\frac{x \cdot 8 + x (- \frac{2}{x^{\frac{1}{2}}}) - 1 \cdot 9 - (8 x) - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3

Simplify the numerator.

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Step 17.3.1

Simplify each term.

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Step 17.3.1.1

Move $8$ to the left of $x$ .

$\frac{8 \cdot x + x (- \frac{2}{x^{\frac{1}{2}}}) - 1 \cdot 9 - (8 x) - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3.1.2

Rewrite using the commutative property of multiplication.

$\frac{8 x - x \frac{2}{x^{\frac{1}{2}}} - 1 \cdot 9 - (8 x) - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3.1.3

Combine $\frac{2}{x^{\frac{1}{2}}}$ and $x$ .

$\frac{8 x - \frac{2 x}{x^{\frac{1}{2}}} - 1 \cdot 9 - (8 x) - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3.1.4

Move $x^{\frac{1}{2}}$ to the numerator using the negative exponent rule $\frac{1}{b^{n}} = b^{- n}$ .

$\frac{8 x - (2 x \cdot x^{- \frac{1}{2}}) - 1 \cdot 9 - (8 x) - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3.1.5

Multiply $x$ by $x^{- \frac{1}{2}}$ by adding the exponents.

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Step 17.3.1.5.1

Move $x^{- \frac{1}{2}}$ .

$\frac{8 x - (2 (x^{- \frac{1}{2}} x)) - 1 \cdot 9 - (8 x) - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3.1.5.2

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

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Step 17.3.1.5.2.1

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

$\frac{8 x - (2 (x^{- \frac{1}{2}} x^{1})) - 1 \cdot 9 - (8 x) - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3.1.5.2.2

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

$\frac{8 x - (2 x^{- \frac{1}{2} + 1}) - 1 \cdot 9 - (8 x) - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3.1.5.3

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

$\frac{8 x - (2 x^{- \frac{1}{2} + \frac{2}{2}}) - 1 \cdot 9 - (8 x) - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3.1.5.4

Combine the numerators over the common denominator.

$\frac{8 x - (2 x^{\frac{- 1 + 2}{2}}) - 1 \cdot 9 - (8 x) - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3.1.5.5

Add $- 1$ and $2$ .

$\frac{8 x - (2 x^{\frac{1}{2}}) - 1 \cdot 9 - (8 x) - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3.1.6

Multiply $2$ by $- 1$ .

$\frac{8 x - 2 x^{\frac{1}{2}} - 1 \cdot 9 - (8 x) - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3.1.7

Multiply $- 1$ by $9$ .

$\frac{8 x - 2 x^{\frac{1}{2}} - 9 - (8 x) - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3.1.8

Multiply $8$ by $- 1$ .

$\frac{8 x - 2 x^{\frac{1}{2}} - 9 - 8 x - (- 4 x^{\frac{1}{2}})}{x^{2}}$

Step 17.3.1.9

Multiply $- 4$ by $- 1$ .

$\frac{8 x - 2 x^{\frac{1}{2}} - 9 - 8 x + 4 x^{\frac{1}{2}}}{x^{2}}$

Step 17.3.2

Combine the opposite terms in $8 x - 2 x^{\frac{1}{2}} - 9 - 8 x + 4 x^{\frac{1}{2}}$ .

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Step 17.3.2.1

Subtract $8 x$ from $8 x$ .

$\frac{- 2 x^{\frac{1}{2}} - 9 + 0 + 4 x^{\frac{1}{2}}}{x^{2}}$

Step 17.3.2.2

Add $- 2 x^{\frac{1}{2}} - 9$ and $0$ .

$\frac{- 2 x^{\frac{1}{2}} - 9 + 4 x^{\frac{1}{2}}}{x^{2}}$

Step 17.3.3

Add $- 2 x^{\frac{1}{2}}$ and $4 x^{\frac{1}{2}}$ .

$\frac{2 x^{\frac{1}{2}} - 9}{x^{2}}$