Algebra Examples

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

Step 1

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

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

Step 2

Differentiate both sides of the equation.

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

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 Product Rule which states that $\frac{d}{d x} [f (x) g (x)]$ is $f (x) \frac{d}{d x} [g (x)] + g (x) \frac{d}{d x} [f (x)]$ where $f (x) = e^{x}$ and $g (x) = {(x^{2} + 1)}^{\frac{1}{2}}$ .

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

Step 4.2

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

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Step 4.2.1

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

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

Step 4.2.2

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

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

Step 4.2.3

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

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

Step 4.3

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

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

Step 4.4

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

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

Step 4.5

Combine the numerators over the common denominator.

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

Step 4.6

Simplify the numerator.

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Step 4.6.1

Multiply $- 1$ by $2$ .

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

Step 4.6.2

Subtract $2$ from $1$ .

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

Step 4.7

Differentiate.

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Step 4.7.1

Move the negative in front of the fraction.

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

Step 4.7.2

Combine fractions.

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Step 4.7.2.1

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

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

Step 4.7.2.2

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

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

Step 4.7.2.3

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

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

Step 4.7.3

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

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

Step 4.7.4

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

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

Step 4.7.5

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

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

Step 4.7.6

Simplify terms.

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Step 4.7.6.1

Add $2 x$ and $0$ .

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

Step 4.7.6.2

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

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

Step 4.7.6.3

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

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

Step 4.7.6.4

Cancel the common factor.

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

Step 4.7.6.5

Rewrite the expression.

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

Step 4.8

Differentiate using the Exponential Rule which states that $\frac{d}{d x} [a^{x}]$ is $a^{x} \ln (a)$ where $a$ = $e$ .

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

Step 4.9

Reorder ${(x^{2} + 1)}^{\frac{1}{2}}$ and $e^{x}$ .

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

Step 4.10

To write $e^{x} {(x^{2} + 1)}^{\frac{1}{2}}$ as a fraction with a common denominator, multiply by $\frac{{(x^{2} + 1)}^{\frac{1}{2}}}{{(x^{2} + 1)}^{\frac{1}{2}}}$ .

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

Step 4.11

Combine the numerators over the common denominator.

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

Step 4.12

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

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Step 4.12.1

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

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

Step 4.12.2

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

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

Step 4.12.3

Combine the numerators over the common denominator.

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

Step 4.12.4

Add $1$ and $1$ .

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

Step 4.12.5

Divide $2$ by $2$ .

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

Step 4.13

Simplify $e^{x} {(x^{2} + 1)}^{1}$ .

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

Step 4.14

Simplify.

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Step 4.14.1

Apply the distributive property.

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

Step 4.14.2

Simplify the numerator.

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Step 4.14.2.1

Multiply $e^{x}$ by $1$ .

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

Step 4.14.2.2

Reorder factors in $x e^{x} + e^{x} x^{2} + e^{x}$ .

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

Step 4.14.3

Reorder terms.

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

Step 4.14.4

Reorder factors in $\frac{e^{x} x + e^{x} x^{2} + e^{x}}{{(x^{2} + 1)}^{\frac{1}{2}}}$ .

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

Step 5

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

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

Step 6

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

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