Calculus Examples

$\frac{1}{2 x + 1}$

Step 1

Rewrite $\frac{1}{2 x + 1}$ as ${(2 x + 1)}^{- 1}$ .

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

Step 2

Differentiate using the chain rule, which states that $\frac{d}{d x} [f (g (x))]$ is $f' (g (x)) g' (x)$ where $f (x) = x^{- 1}$ and $g (x) = 2 x + 1$ .

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Step 2.1

To apply the Chain Rule, set $u$ as $2 x + 1$ .

$\frac{d}{d u} [u^{- 1}] \frac{d}{d x} [2 x + 1]$

Step 2.2

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

$- u^{- 2} \frac{d}{d x} [2 x + 1]$

Step 2.3

Replace all occurrences of $u$ with $2 x + 1$ .

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

Step 3

Differentiate.

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Step 3.1

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

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

Step 3.2

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

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

Step 3.3

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

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

Step 3.4

Multiply $2$ by $1$ .

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

Step 3.5

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

$- {(2 x + 1)}^{- 2} (2 + 0)$

Step 3.6

Simplify the expression.

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Step 3.6.1

Add $2$ and $0$ .

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

Step 3.6.2

Multiply $2$ by $- 1$ .

$- 2 {(2 x + 1)}^{- 2}$

Step 4

Simplify.

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Step 4.1

Rewrite the expression using the negative exponent rule $b^{- n} = \frac{1}{b^{n}}$ .

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

Step 4.2

Combine terms.

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Step 4.2.1

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

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

Step 4.2.2

Move the negative in front of the fraction.

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