Calculus Examples

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

Step 1

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

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

Step 2

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

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

Step 3

Differentiate.

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Step 3.1

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

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

Step 3.2

Since $9$ is constant with respect to $x$ , the derivative of $9 x$ with respect to $x$ is $9 \frac{d}{d x} [x]$ .

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

Step 3.3

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

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

Step 3.4

Multiply $9$ by $1$ .

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

Step 3.5

Since $8$ is constant with respect to $x$ , the derivative of $8$ with respect to $x$ is $0$ .

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

Step 3.6

Simplify the expression.

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Step 3.6.1

Add $9$ and $0$ .

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

Step 3.6.2

Move $9$ to the left of $4 x^{2} - \frac{x}{2}$ .

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

Step 3.7

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

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

Step 3.8

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

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

Step 3.9

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

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

Step 3.10

Multiply $2$ by $4$ .

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

Step 3.11

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

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

Step 3.12

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

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

Step 3.13

Multiply $- 1$ by $1$ .

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

Step 4

Simplify.

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Step 4.1

Apply the distributive property.

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

Step 4.2

Apply the distributive property.

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

Step 4.3

Apply the distributive property.

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

Step 4.4

Apply the distributive property.

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

Step 4.5

Combine terms.

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Step 4.5.1

Multiply $4$ by $9$ .

$36 x^{2} + 9 (- \frac{x}{2}) + 9 x (8 x) + 8 (8 x) + 9 x (- \frac{1}{2}) + 8 (- \frac{1}{2})$

Step 4.5.2

Multiply $- 1$ by $9$ .

$36 x^{2} - 9 \frac{x}{2} + 9 x (8 x) + 8 (8 x) + 9 x (- \frac{1}{2}) + 8 (- \frac{1}{2})$

Step 4.5.3

Combine $- 9$ and $\frac{x}{2}$ .

$36 x^{2} + \frac{- 9 x}{2} + 9 x (8 x) + 8 (8 x) + 9 x (- \frac{1}{2}) + 8 (- \frac{1}{2})$

Step 4.5.4

Move the negative in front of the fraction.

$36 x^{2} - \frac{9 x}{2} + 9 x (8 x) + 8 (8 x) + 9 x (- \frac{1}{2}) + 8 (- \frac{1}{2})$

Step 4.5.5

Multiply $8$ by $9$ .

$36 x^{2} - \frac{9 x}{2} + 72 x \cdot x + 8 (8 x) + 9 x (- \frac{1}{2}) + 8 (- \frac{1}{2})$

Step 4.5.6

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

$36 x^{2} - \frac{9 x}{2} + 72 (x^{1} x) + 8 (8 x) + 9 x (- \frac{1}{2}) + 8 (- \frac{1}{2})$

Step 4.5.7

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

$36 x^{2} - \frac{9 x}{2} + 72 (x^{1} x^{1}) + 8 (8 x) + 9 x (- \frac{1}{2}) + 8 (- \frac{1}{2})$

Step 4.5.8

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

$36 x^{2} - \frac{9 x}{2} + 72 x^{1 + 1} + 8 (8 x) + 9 x (- \frac{1}{2}) + 8 (- \frac{1}{2})$

Step 4.5.9

Add $1$ and $1$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 8 (8 x) + 9 x (- \frac{1}{2}) + 8 (- \frac{1}{2})$

Step 4.5.10

Multiply $8$ by $8$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x + 9 x (- \frac{1}{2}) + 8 (- \frac{1}{2})$

Step 4.5.11

Multiply $- 1$ by $9$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x - 9 x \frac{1}{2} + 8 (- \frac{1}{2})$

Step 4.5.12

Combine $- 9$ and $\frac{1}{2}$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x + x \frac{- 9}{2} + 8 (- \frac{1}{2})$

Step 4.5.13

Combine $x$ and $\frac{- 9}{2}$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x + \frac{x \cdot - 9}{2} + 8 (- \frac{1}{2})$

Step 4.5.14

Move $- 9$ to the left of $x$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x + \frac{- 9 \cdot x}{2} + 8 (- \frac{1}{2})$

Step 4.5.15

Move the negative in front of the fraction.

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x - \frac{9 x}{2} + 8 (- \frac{1}{2})$

Step 4.5.16

Multiply $- 1$ by $8$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x - \frac{9 x}{2} - 8 (\frac{1}{2})$

Step 4.5.17

Combine $- 8$ and $\frac{1}{2}$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x - \frac{9 x}{2} + \frac{- 8}{2}$

Step 4.5.18

Cancel the common factor of $- 8$ and $2$ .

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Step 4.5.18.1

Factor $2$ out of $- 8$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x - \frac{9 x}{2} + \frac{2 \cdot - 4}{2}$

Step 4.5.18.2

Cancel the common factors.

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Step 4.5.18.2.1

Factor $2$ out of $2$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x - \frac{9 x}{2} + \frac{2 \cdot - 4}{2 (1)}$

Step 4.5.18.2.2

Cancel the common factor.

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x - \frac{9 x}{2} + \frac{2 \cdot - 4}{2 \cdot 1}$

Step 4.5.18.2.3

Rewrite the expression.

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x - \frac{9 x}{2} + \frac{- 4}{1}$

Step 4.5.18.2.4

Divide $- 4$ by $1$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x - \frac{9 x}{2} - 4$

Step 4.5.19

To write $64 x$ as a fraction with a common denominator, multiply by $\frac{2}{2}$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + 64 x \cdot \frac{2}{2} - \frac{9 x}{2} - 4$

Step 4.5.20

Combine $64 x$ and $\frac{2}{2}$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + \frac{64 x \cdot 2}{2} - \frac{9 x}{2} - 4$

Step 4.5.21

Combine the numerators over the common denominator.

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + \frac{64 x \cdot 2 - 9 x}{2} - 4$

Step 4.5.22

Multiply $2$ by $64$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + \frac{128 x - 9 x}{2} - 4$

Step 4.5.23

Subtract $9 x$ from $128 x$ .

$36 x^{2} - \frac{9 x}{2} + 72 x^{2} + \frac{119 x}{2} - 4$

Step 4.5.24

Add $36 x^{2}$ and $72 x^{2}$ .

$108 x^{2} - \frac{9 x}{2} + \frac{119 x}{2} - 4$

Step 4.5.25

Combine the numerators over the common denominator.

$108 x^{2} + \frac{- 9 x + 119 x}{2} - 4$

Step 4.5.26

Add $- 9 x$ and $119 x$ .

$108 x^{2} + \frac{110 x}{2} - 4$

Step 4.5.27

Cancel the common factor of $110$ and $2$ .

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Step 4.5.27.1

Factor $2$ out of $110 x$ .

$108 x^{2} + \frac{2 (55 x)}{2} - 4$

Step 4.5.27.2

Cancel the common factors.

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Step 4.5.27.2.1

Factor $2$ out of $2$ .

$108 x^{2} + \frac{2 (55 x)}{2 (1)} - 4$

Step 4.5.27.2.2

Cancel the common factor.

$108 x^{2} + \frac{2 (55 x)}{2 \cdot 1} - 4$

Step 4.5.27.2.3

Rewrite the expression.

$108 x^{2} + \frac{55 x}{1} - 4$

Step 4.5.27.2.4

Divide $55 x$ by $1$ .

$108 x^{2} + 55 x - 4$