Calculus Examples

$y = 2 x^{2} \sqrt{2 - x}$

Step 1

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

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

Step 2

Differentiate both sides of the equation.

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

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

Since $2$ is constant with respect to $x$ , the derivative of $2 x^{2} {(2 - x)}^{\frac{1}{2}}$ with respect to $x$ is $2 \frac{d}{d x} [x^{2} {(2 - x)}^{\frac{1}{2}}]$ .

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

Step 4.2

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

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

Step 4.3

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 $g (x) = 2 - x$ .

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Step 4.3.1

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

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

Step 4.3.2

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

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

Step 4.3.3

Replace all occurrences of $u$ with $2 - x$ .

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

Step 4.4

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

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

Step 4.5

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

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

Step 4.6

Combine the numerators over the common denominator.

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

Step 4.7

Simplify the numerator.

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Step 4.7.1

Multiply $- 1$ by $2$ .

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

Step 4.7.2

Subtract $2$ from $1$ .

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

Step 4.8

Combine fractions.

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Step 4.8.1

Move the negative in front of the fraction.

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

Step 4.8.2

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

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

Step 4.8.3

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

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

Step 4.8.4

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

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

Step 4.9

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

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

Step 4.10

Since $2$ is constant with respect to $x$ , the derivative of $2$ with respect to $x$ is $0$ .

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

Step 4.11

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

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

Step 4.12

Since $- 1$ is constant with respect to $x$ , the derivative of $- x$ with respect to $x$ is $- \frac{d}{d x} [x]$ .

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

Step 4.13

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

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

Step 4.14

Combine fractions.

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Step 4.14.1

Multiply $- 1$ by $1$ .

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

Step 4.14.2

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

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

Step 4.14.3

Simplify the expression.

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Step 4.14.3.1

Move $- 1$ to the left of $x^{2}$ .

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

Step 4.14.3.2

Rewrite $- 1 x^{2}$ as $- x^{2}$ .

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

Step 4.14.3.3

Move the negative in front of the fraction.

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

Step 4.15

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

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

Step 4.16

Reorder.

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Step 4.16.1

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

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

Step 4.16.2

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

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

Step 4.17

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

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

Step 4.18

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

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

Step 4.19

Combine the numerators over the common denominator.

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

Step 4.20

Multiply $2$ by $2$ .

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

Step 4.21

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

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Step 4.21.1

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

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

Step 4.21.2

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

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

Step 4.21.3

Combine the numerators over the common denominator.

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

Step 4.21.4

Add $1$ and $1$ .

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

Step 4.21.5

Divide $2$ by $2$ .

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

Step 4.22

Simplify $4 x {(- x + 2)}^{1}$ .

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

Step 4.23

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

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

Step 4.24

Cancel the common factor.

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

Step 4.25

Rewrite the expression.

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

Step 4.26

Simplify.

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Step 4.26.1

Apply the distributive property.

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

Step 4.26.2

Simplify the numerator.

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Step 4.26.2.1

Simplify each term.

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Step 4.26.2.1.1

Rewrite using the commutative property of multiplication.

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

Step 4.26.2.1.2

Multiply $x$ by $x$ by adding the exponents.

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Step 4.26.2.1.2.1

Move $x$ .

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

Step 4.26.2.1.2.2

Multiply $x$ by $x$ .

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

Step 4.26.2.1.3

Multiply $4$ by $- 1$ .

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

Step 4.26.2.1.4

Multiply $2$ by $4$ .

$\frac{- x^{2} - 4 x^{2} + 8 x}{{(- x + 2)}^{\frac{1}{2}}}$

Step 4.26.2.2

Subtract $4 x^{2}$ from $- x^{2}$ .

$\frac{- 5 x^{2} + 8 x}{{(- x + 2)}^{\frac{1}{2}}}$

Step 4.26.3

Factor $x$ out of $- 5 x^{2} + 8 x$ .

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Step 4.26.3.1

Factor $x$ out of $- 5 x^{2}$ .

$\frac{x (- 5 x) + 8 x}{{(- x + 2)}^{\frac{1}{2}}}$

Step 4.26.3.2

Factor $x$ out of $8 x$ .

$\frac{x (- 5 x) + x \cdot 8}{{(- x + 2)}^{\frac{1}{2}}}$

Step 4.26.3.3

Factor $x$ out of $x (- 5 x) + x \cdot 8$ .

$\frac{x (- 5 x + 8)}{{(- x + 2)}^{\frac{1}{2}}}$

Step 4.26.4

Factor $- 1$ out of $- 5 x$ .

$\frac{x (- (5 x) + 8)}{{(- x + 2)}^{\frac{1}{2}}}$

Step 4.26.5

Rewrite $8$ as $- 1 (- 8)$ .

$\frac{x (- (5 x) - 1 (- 8))}{{(- x + 2)}^{\frac{1}{2}}}$

Step 4.26.6

Factor $- 1$ out of $- (5 x) - 1 (- 8)$ .

$\frac{x (- (5 x - 8))}{{(- x + 2)}^{\frac{1}{2}}}$

Step 4.26.7

Rewrite $- (5 x - 8)$ as $- 1 (5 x - 8)$ .

$\frac{x (- 1 (5 x - 8))}{{(- x + 2)}^{\frac{1}{2}}}$

Step 4.26.8

Move the negative in front of the fraction.

$- \frac{x (5 x - 8)}{{(- x + 2)}^{\frac{1}{2}}}$

Step 5

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

$y' = - \frac{x (5 x - 8)}{{(- x + 2)}^{\frac{1}{2}}}$

Step 6

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

$\frac{d y}{d x} = - \frac{x (5 x - 8)}{{(- x + 2)}^{\frac{1}{2}}}$