Calculus Examples

$y = \frac{2 x}{x^{2} - 9}$

Step 1

Since $2$ is constant with respect to $x$ , the derivative of $\frac{2 x}{x^{2} - 9}$ with respect to $x$ is $2 \frac{d}{d x} [\frac{x}{x^{2} - 9}]$ .

$2 \frac{d}{d x} [\frac{x}{x^{2} - 9}]$

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 $f (x) = x$ and $g (x) = x^{2} - 9$ .

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

Step 3

Differentiate.

Tap for more steps...

Step 3.1

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

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

Step 3.2

Multiply $x^{2} - 9$ by $1$ .

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

Step 3.3

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

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

Step 3.4

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

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

Step 3.5

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

$2 \frac{x^{2} - 9 - x (2 x + 0)}{{(x^{2} - 9)}^{2}}$

Step 3.6

Simplify the expression.

Tap for more steps...

Step 3.6.1

Add $2 x$ and $0$ .

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

Step 3.6.2

Multiply $2$ by $- 1$ .

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

Step 4

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

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

Step 5

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

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

Step 6

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

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

Step 7

Add $1$ and $1$ .

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

Step 8

Subtract $2 x^{2}$ from $x^{2}$ .

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

Step 9

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

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

Step 10

Simplify.

Tap for more steps...

Step 10.1

Apply the distributive property.

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

Step 10.2

Simplify each term.

Tap for more steps...

Step 10.2.1

Multiply $- 1$ by $2$ .

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

Step 10.2.2

Multiply $2$ by $- 9$ .

$\frac{- 2 x^{2} - 18}{{(x^{2} - 9)}^{2}}$