Calculus Examples

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

Step 1

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

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

Step 2

Differentiate both sides of the equation.

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

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

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

Step 4.2

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

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Step 4.2.1

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

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

Step 4.2.2

Cancel the common factor of $2$ .

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Step 4.2.2.1

Cancel the common factor.

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

Step 4.2.2.2

Rewrite the expression.

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

Step 4.3

Simplify.

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

Step 4.4

Differentiate using the Power Rule.

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Step 4.4.1

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

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

Step 4.4.2

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

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

Step 4.5

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 4.5.1

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

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

Step 4.5.2

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

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

Step 4.5.3

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

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

Step 4.6

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

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

Step 4.7

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

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

Step 4.8

Combine the numerators over the common denominator.

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

Step 4.9

Simplify the numerator.

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Step 4.9.1

Multiply $- 1$ by $2$ .

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

Step 4.9.2

Subtract $2$ from $1$ .

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

Step 4.10

Combine fractions.

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Step 4.10.1

Move the negative in front of the fraction.

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

Step 4.10.2

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

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

Step 4.10.3

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

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

Step 4.10.4

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

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

Step 4.11

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

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

Step 4.12

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

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

Step 4.13

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

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

Step 4.14

Combine fractions.

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Step 4.14.1

Add $2 x$ and $0$ .

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

Step 4.14.2

Multiply $2$ by $- 1$ .

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

Step 4.14.3

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

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

Step 4.14.4

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

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

Step 4.15

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

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

Step 4.16

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

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

Step 4.17

Add $1$ and $2$ .

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

Step 4.18

Factor $2$ out of $- 2 x^{3}$ .

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

Step 4.19

Cancel the common factors.

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Step 4.19.1

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

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

Step 4.19.2

Cancel the common factor.

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

Step 4.19.3

Rewrite the expression.

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

Step 4.20

Move the negative in front of the fraction.

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

Step 4.21

Combine $2 {(x^{2} + 1)}^{\frac{1}{2}} x$ and $- \frac{x^{3}}{{(x^{2} + 1)}^{\frac{1}{2}}}$ using a common denominator.

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Step 4.21.1

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

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

Step 4.21.2

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

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

Step 4.21.3

Combine the numerators over the common denominator.

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

Step 4.22

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

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Step 4.22.1

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

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

Step 4.22.2

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

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

Step 4.22.3

Combine the numerators over the common denominator.

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

Step 4.22.4

Add $1$ and $1$ .

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

Step 4.22.5

Divide $2$ by $2$ .

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

Step 4.23

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

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

Step 4.24

Rewrite $\frac{\frac{2 x (x^{2} + 1) - x^{3}}{{(x^{2} + 1)}^{\frac{1}{2}}}}{x^{2} + 1}$ as a product.

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

Step 4.25

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

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

Step 4.26

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

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Step 4.26.1

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

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Step 4.26.1.1

Raise $x^{2} + 1$ to the power of $1$ .

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

Step 4.26.1.2

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

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

Step 4.26.2

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

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

Step 4.26.3

Combine the numerators over the common denominator.

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

Step 4.26.4

Add $1$ and $2$ .

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

Step 4.27

Simplify.

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Step 4.27.1

Apply the distributive property.

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

Step 4.27.2

Simplify the numerator.

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Step 4.27.2.1

Simplify each term.

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Step 4.27.2.1.1

Multiply $x$ by $x^{2}$ by adding the exponents.

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Step 4.27.2.1.1.1

Move $x^{2}$ .

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

Step 4.27.2.1.1.2

Multiply $x^{2}$ by $x$ .

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Step 4.27.2.1.1.2.1

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

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

Step 4.27.2.1.1.2.2

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

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

Step 4.27.2.1.1.3

Add $2$ and $1$ .

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

Step 4.27.2.1.2

Multiply $2$ by $1$ .

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

Step 4.27.2.2

Subtract $x^{3}$ from $2 x^{3}$ .

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

Step 4.27.3

Factor $x$ out of $x^{3} + 2 x$ .

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Step 4.27.3.1

Factor $x$ out of $x^{3}$ .

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

Step 4.27.3.2

Factor $x$ out of $2 x$ .

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

Step 4.27.3.3

Factor $x$ out of $x \cdot x^{2} + x \cdot 2$ .

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

Step 5

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

$y' = \frac{x (x^{2} + 2)}{{(x^{2} + 1)}^{\frac{3}{2}}}$

Step 6

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

$\frac{d y}{d x} = \frac{x (x^{2} + 2)}{{(x^{2} + 1)}^{\frac{3}{2}}}$