Calculus Examples

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

Step 1

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 $f (x) = 4 - 3 x$ and $g (x) = 3 x^{2} + x$ .

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

Step 2

Differentiate.

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Step 2.1

By the Sum Rule, the derivative of $4 - 3 x$ with respect to $x$ is $\frac{d}{d x} [4] + \frac{d}{d x} [- 3 x]$ .

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

Step 2.2

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

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

Step 2.3

Add $0$ and $\frac{d}{d x} [- 3 x]$ .

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

Step 2.4

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

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

Step 2.5

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

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

Step 2.6

Simplify the expression.

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Step 2.6.1

Multiply $- 3$ by $1$ .

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

Step 2.6.2

Move $- 3$ to the left of $3 x^{2} + x$ .

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

Step 2.7

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

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

Step 2.8

Since $3$ is constant with respect to $x$ , the derivative of $3 x^{2}$ with respect to $x$ is $3 \frac{d}{d x} [x^{2}]$ .

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

Step 2.9

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

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

Step 2.10

Multiply $2$ by $3$ .

$\frac{- 3 (3 x^{2} + x) - (4 - 3 x) (6 x + \frac{d}{d x} [x])}{{(3 x^{2} + x)}^{2}}$

Step 2.11

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

$\frac{- 3 (3 x^{2} + x) - (4 - 3 x) (6 x + 1)}{{(3 x^{2} + x)}^{2}}$

Step 3

Simplify.

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Step 3.1

Apply the distributive property.

$\frac{- 3 (3 x^{2}) - 3 x - (4 - 3 x) (6 x + 1)}{{(3 x^{2} + x)}^{2}}$

Step 3.2

Apply the distributive property.

$\frac{- 3 (3 x^{2}) - 3 x + (- 1 \cdot 4 - (- 3 x)) (6 x + 1)}{{(3 x^{2} + x)}^{2}}$

Step 3.3

Simplify the numerator.

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Step 3.3.1

Simplify each term.

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Step 3.3.1.1

Multiply $3$ by $- 3$ .

$\frac{- 9 x^{2} - 3 x + (- 1 \cdot 4 - (- 3 x)) (6 x + 1)}{{(3 x^{2} + x)}^{2}}$

Step 3.3.1.2

Simplify each term.

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Step 3.3.1.2.1

Multiply $- 1$ by $4$ .

$\frac{- 9 x^{2} - 3 x + (- 4 - (- 3 x)) (6 x + 1)}{{(3 x^{2} + x)}^{2}}$

Step 3.3.1.2.2

Multiply $- 3$ by $- 1$ .

$\frac{- 9 x^{2} - 3 x + (- 4 + 3 x) (6 x + 1)}{{(3 x^{2} + x)}^{2}}$

Step 3.3.1.3

Expand $(- 4 + 3 x) (6 x + 1)$ using the FOIL Method.

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Step 3.3.1.3.1

Apply the distributive property.

$\frac{- 9 x^{2} - 3 x - 4 (6 x + 1) + 3 x (6 x + 1)}{{(3 x^{2} + x)}^{2}}$

Step 3.3.1.3.2

Apply the distributive property.

$\frac{- 9 x^{2} - 3 x - 4 (6 x) - 4 \cdot 1 + 3 x (6 x + 1)}{{(3 x^{2} + x)}^{2}}$

Step 3.3.1.3.3

Apply the distributive property.

$\frac{- 9 x^{2} - 3 x - 4 (6 x) - 4 \cdot 1 + 3 x (6 x) + 3 x \cdot 1}{{(3 x^{2} + x)}^{2}}$

Step 3.3.1.4

Simplify and combine like terms.

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Step 3.3.1.4.1

Simplify each term.

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Step 3.3.1.4.1.1

Multiply $6$ by $- 4$ .

$\frac{- 9 x^{2} - 3 x - 24 x - 4 \cdot 1 + 3 x (6 x) + 3 x \cdot 1}{{(3 x^{2} + x)}^{2}}$

Step 3.3.1.4.1.2

Multiply $- 4$ by $1$ .

$\frac{- 9 x^{2} - 3 x - 24 x - 4 + 3 x (6 x) + 3 x \cdot 1}{{(3 x^{2} + x)}^{2}}$

Step 3.3.1.4.1.3

Rewrite using the commutative property of multiplication.

$\frac{- 9 x^{2} - 3 x - 24 x - 4 + 3 \cdot 6 x \cdot x + 3 x \cdot 1}{{(3 x^{2} + x)}^{2}}$

Step 3.3.1.4.1.4

Multiply $x$ by $x$ by adding the exponents.

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Step 3.3.1.4.1.4.1

Move $x$ .

$\frac{- 9 x^{2} - 3 x - 24 x - 4 + 3 \cdot 6 (x \cdot x) + 3 x \cdot 1}{{(3 x^{2} + x)}^{2}}$

Step 3.3.1.4.1.4.2

Multiply $x$ by $x$ .

$\frac{- 9 x^{2} - 3 x - 24 x - 4 + 3 \cdot 6 x^{2} + 3 x \cdot 1}{{(3 x^{2} + x)}^{2}}$

Step 3.3.1.4.1.5

Multiply $3$ by $6$ .

$\frac{- 9 x^{2} - 3 x - 24 x - 4 + 18 x^{2} + 3 x \cdot 1}{{(3 x^{2} + x)}^{2}}$

Step 3.3.1.4.1.6

Multiply $3$ by $1$ .

$\frac{- 9 x^{2} - 3 x - 24 x - 4 + 18 x^{2} + 3 x}{{(3 x^{2} + x)}^{2}}$

Step 3.3.1.4.2

Add $- 24 x$ and $3 x$ .

$\frac{- 9 x^{2} - 3 x - 21 x - 4 + 18 x^{2}}{{(3 x^{2} + x)}^{2}}$

Step 3.3.2

Add $- 9 x^{2}$ and $18 x^{2}$ .

$\frac{9 x^{2} - 3 x - 21 x - 4}{{(3 x^{2} + x)}^{2}}$

Step 3.3.3

Subtract $21 x$ from $- 3 x$ .

$\frac{9 x^{2} - 24 x - 4}{{(3 x^{2} + x)}^{2}}$

Step 3.4

Simplify the denominator.

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Step 3.4.1

Factor $x$ out of $3 x^{2} + x$ .

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Step 3.4.1.1

Factor $x$ out of $3 x^{2}$ .

$\frac{9 x^{2} - 24 x - 4}{{(x (3 x) + x)}^{2}}$

Step 3.4.1.2

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

$\frac{9 x^{2} - 24 x - 4}{{(x (3 x) + x^{1})}^{2}}$

Step 3.4.1.3

Factor $x$ out of $x^{1}$ .

$\frac{9 x^{2} - 24 x - 4}{{(x (3 x) + x \cdot 1)}^{2}}$

Step 3.4.1.4

Factor $x$ out of $x (3 x) + x \cdot 1$ .

$\frac{9 x^{2} - 24 x - 4}{{(x (3 x + 1))}^{2}}$

Step 3.4.2

Apply the product rule to $x (3 x + 1)$ .

$\frac{9 x^{2} - 24 x - 4}{x^{2} {(3 x + 1)}^{2}}$