Calculus Examples

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

Step 1

Differentiate both sides of the equation.

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

Step 2

The derivative of $y$ with respect to $x$ is $y'$ .

$y'$

Step 3

Differentiate the right side of the equation.

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Step 3.1

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 $f (x) = 1 + 3 x$ and $g (x) = 2 - x^{2}$ .

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

Step 3.2

Differentiate.

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Step 3.2.1

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

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

Step 3.2.2

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

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

Step 3.2.3

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

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

Step 3.2.4

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

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

Step 3.2.5

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

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

Step 3.2.6

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

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

Step 3.2.7

Multiply $3$ by $1$ .

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

Step 3.2.8

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

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

Step 3.2.9

Since $2$ is constant with respect to $x$ , the derivative of $2$ with respect to $x$ is $0$ .

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

Step 3.2.10

Add $0$ and $\frac{d}{d x} [- x^{2}]$ .

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

Step 3.2.11

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

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

Step 3.2.12

Multiply.

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Step 3.2.12.1

Multiply $- 1$ by $- 1$ .

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

Step 3.2.12.2

Multiply $1 + 3 x$ by $1$ .

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

Step 3.2.13

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

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

Step 3.2.14

Move $2$ to the left of $1 + 3 x$ .

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

Step 3.3

Simplify.

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Step 3.3.1

Apply the distributive property.

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

Step 3.3.2

Apply the distributive property.

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

Step 3.3.3

Apply the distributive property.

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

Step 3.3.4

Simplify the numerator.

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Step 3.3.4.1

Simplify each term.

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Step 3.3.4.1.1

Multiply $3$ by $2$ .

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

Step 3.3.4.1.2

Multiply $- 1$ by $3$ .

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

Step 3.3.4.1.3

Multiply $2$ by $1$ .

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

Step 3.3.4.1.4

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

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Step 3.3.4.1.4.1

Move $x$ .

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

Step 3.3.4.1.4.2

Multiply $x$ by $x$ .

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

Step 3.3.4.1.5

Multiply $3$ by $2$ .

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

Step 3.3.4.2

Add $- 3 x^{2}$ and $6 x^{2}$ .

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

Step 3.3.5

Reorder terms.

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

Step 4

Reform the equation by setting the left side equal to the right side.

$y' = \frac{3 x^{2} + 2 x + 6}{{(- x^{2} + 2)}^{2}}$

Step 5

Replace $y'$ with $\frac{d y}{d x}$ .

$\frac{d y}{d x} = \frac{3 x^{2} + 2 x + 6}{{(- x^{2} + 2)}^{2}}$