Calculus Examples

$y = \sqrt{x + \sqrt{x}}$

Step 1

Rewrite the right side with rational exponents.

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Step 1.1

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

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

Step 1.2

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

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

Step 2

Differentiate both sides of the equation.

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

Step 3

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

$y'$

Step 4

Differentiate the right side of the equation.

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Step 4.1

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 $g (x) = x + x^{\frac{1}{2}}$ .

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Step 4.1.1

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

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

Step 4.1.2

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

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

Step 4.1.3

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

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

Step 4.2

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

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

Step 4.3

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

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

Step 4.4

Combine the numerators over the common denominator.

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

Step 4.5

Simplify the numerator.

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Step 4.5.1

Multiply $- 1$ by $2$ .

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

Step 4.5.2

Subtract $2$ from $1$ .

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

Step 4.6

Combine fractions.

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Step 4.6.1

Move the negative in front of the fraction.

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

Step 4.6.2

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

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

Step 4.6.3

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

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

Step 4.7

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

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

Step 4.8

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

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

Step 4.9

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

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

Step 4.10

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

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

Step 4.11

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

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

Step 4.12

Combine the numerators over the common denominator.

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

Step 4.13

Simplify the numerator.

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Step 4.13.1

Multiply $- 1$ by $2$ .

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

Step 4.13.2

Subtract $2$ from $1$ .

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

Step 4.14

Move the negative in front of the fraction.

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

Step 4.15

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

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

Step 4.16

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

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

Step 4.17

Simplify.

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Step 4.17.1

Reorder the factors of $\frac{1}{2 {(x + x^{\frac{1}{2}})}^{\frac{1}{2}}} (1 + \frac{1}{2 x^{\frac{1}{2}}})$ .

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

Step 4.17.2

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

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

Step 4.17.3

Simplify the numerator.

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Step 4.17.3.1

Write $1$ as a fraction with a common denominator.

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

Step 4.17.3.2

Combine the numerators over the common denominator.

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

Step 4.17.4

Multiply the numerator by the reciprocal of the denominator.

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

Step 4.17.5

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

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Step 4.17.5.1

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

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

Step 4.17.5.2

Multiply $2$ by $2$ .

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

Step 5

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

$y' = \frac{2 x^{\frac{1}{2}} + 1}{4 x^{\frac{1}{2}} {(x + x^{\frac{1}{2}})}^{\frac{1}{2}}}$

Step 6

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

$\frac{d y}{d x} = \frac{2 x^{\frac{1}{2}} + 1}{4 x^{\frac{1}{2}} {(x + x^{\frac{1}{2}})}^{\frac{1}{2}}}$