Calculus Examples

$f (x) = \sqrt{\frac{1 - 2 x}{1 + 2 x}}$

Step 1

Use $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$ to rewrite $\sqrt{\frac{1 - 2 x}{1 + 2 x}}$ as ${(\frac{1 - 2 x}{1 + 2 x})}^{\frac{1}{2}}$ .

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

Step 2

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

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Step 2.1

To apply the Chain Rule, set $u$ as $\frac{1 - 2 x}{1 + 2 x}$ .

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

Step 2.2

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

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

Step 2.3

Replace all occurrences of $u$ with $\frac{1 - 2 x}{1 + 2 x}$ .

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

Step 3

To write $- 1$ as a fraction with a common denominator, multiply by $\frac{2}{2}$ .

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

Step 4

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

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

Step 5

Combine the numerators over the common denominator.

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

Step 6

Simplify the numerator.

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Step 6.1

Multiply $- 1$ by $2$ .

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

Step 6.2

Subtract $2$ from $1$ .

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

Step 7

Move the negative in front of the fraction.

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

Step 8

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 $f (x) = 1 - 2 x$ and $g (x) = 1 + 2 x$ .

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

Step 9

Differentiate.

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Step 9.1

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

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

Step 9.2

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

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

Step 9.3

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

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

Step 9.4

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

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

Step 9.5

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

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

Step 9.6

Simplify the expression.

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Step 9.6.1

Multiply $- 2$ by $1$ .

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

Step 9.6.2

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

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

Step 9.7

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

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

Step 9.8

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

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

Step 9.9

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

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

Step 9.10

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

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

Step 9.11

Multiply $2$ by $- 1$ .

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

Step 9.12

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

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

Step 9.13

Simplify terms.

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Step 9.13.1

Multiply $- 2$ by $1$ .

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

Step 9.13.2

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

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

Step 9.13.3

Move $2$ to the left of ${(1 + 2 x)}^{2}$ .

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

Step 9.13.4

Cancel the common factor of $- 2 (1 + 2 x) - 2 (1 - 2 x)$ and $2$ .

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Step 9.13.4.1

Factor $2$ out of $- 2 (1 + 2 x)$ .

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

Step 9.13.4.2

Factor $2$ out of $- 2 (1 - 2 x)$ .

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

Step 9.13.4.3

Factor $2$ out of $2 (- (1 + 2 x)) + 2 (- (1 - 2 x))$ .

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

Step 9.13.4.4

Cancel the common factors.

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Step 9.13.4.4.1

Factor $2$ out of $2 {(1 + 2 x)}^{2}$ .

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

Step 9.13.4.4.2

Cancel the common factor.

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

Step 9.13.4.4.3

Rewrite the expression.

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

Step 10

Simplify.

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Step 10.1

Change the sign of the exponent by rewriting the base as its reciprocal.

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

Step 10.2

Apply the product rule to $\frac{1 + 2 x}{1 - 2 x}$ .

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

Step 10.3

Apply the distributive property.

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

Step 10.4

Apply the distributive property.

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

Step 10.5

Combine terms.

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Step 10.5.1

Multiply $- 1$ by $1$ .

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

Step 10.5.2

Multiply $2$ by $- 1$ .

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

Step 10.5.3

Multiply $- 1$ by $1$ .

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

Step 10.5.4

Multiply $- 2$ by $- 1$ .

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

Step 10.5.5

Subtract $1$ from $- 1$ .

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

Step 10.5.6

Add $- 2 x$ and $2 x$ .

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

Step 10.5.7

Subtract $2$ from $0$ .

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

Step 10.5.8

Move the negative in front of the fraction.

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

Step 10.5.9

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

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

Step 10.5.10

Move $2$ to the left of ${(1 + 2 x)}^{\frac{1}{2}}$ .

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

Step 10.5.11

Move ${(1 + 2 x)}^{\frac{1}{2}}$ to the denominator using the negative exponent rule $b^{n} = \frac{1}{b^{- n}}$ .

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

Step 10.5.12

Multiply ${(1 + 2 x)}^{2}$ by ${(1 + 2 x)}^{- \frac{1}{2}}$ by adding the exponents.

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Step 10.5.12.1

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

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

Step 10.5.12.2

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

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

Step 10.5.12.3

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

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

Step 10.5.12.4

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

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

Step 10.5.12.5

Combine the numerators over the common denominator.

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

Step 10.5.12.6

Simplify the numerator.

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Step 10.5.12.6.1

Multiply $2$ by $2$ .

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

Step 10.5.12.6.2

Add $- 1$ and $4$ .

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