Calculus Examples

$x^{3} - 3 x^{2} y + 2 x y^{2} = 12$

Step 1

Differentiate both sides of the equation.

$\frac{d}{d x} (x^{3} - 3 x^{2} y + 2 x y^{2}) = \frac{d}{d x} (12)$

Step 2

Differentiate the left side of the equation.

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Step 2.1

Differentiate.

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Step 2.1.1

By the Sum Rule, the derivative of $x^{3} - 3 x^{2} y + 2 x y^{2}$ with respect to $x$ is $\frac{d}{d x} [x^{3}] + \frac{d}{d x} [- 3 x^{2} y] + \frac{d}{d x} [2 x y^{2}]$ .

$\frac{d}{d x} [x^{3}] + \frac{d}{d x} [- 3 x^{2} y] + \frac{d}{d x} [2 x y^{2}]$

Step 2.1.2

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 3$ .

$3 x^{2} + \frac{d}{d x} [- 3 x^{2} y] + \frac{d}{d x} [2 x y^{2}]$

Step 2.2

Evaluate $\frac{d}{d x} [- 3 x^{2} y]$ .

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Step 2.2.1

Since $- 3$ is constant with respect to $x$ , the derivative of $- 3 x^{2} y$ with respect to $x$ is $- 3 \frac{d}{d x} [x^{2} y]$ .

$3 x^{2} - 3 \frac{d}{d x} [x^{2} y] + \frac{d}{d x} [2 x y^{2}]$

Step 2.2.2

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 $g (x) = y$ .

$3 x^{2} - 3 (x^{2} \frac{d}{d x} [y] + y \frac{d}{d x} [x^{2}]) + \frac{d}{d x} [2 x y^{2}]$

Step 2.2.3

Rewrite $\frac{d}{d x} [y]$ as $y'$ .

$3 x^{2} - 3 (x^{2} y' + y \frac{d}{d x} [x^{2}]) + \frac{d}{d x} [2 x y^{2}]$

Step 2.2.4

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

$3 x^{2} - 3 (x^{2} y' + y (2 x)) + \frac{d}{d x} [2 x y^{2}]$

Step 2.2.5

Move $2$ to the left of $y$ .

$3 x^{2} - 3 (x^{2} y' + 2 y x) + \frac{d}{d x} [2 x y^{2}]$

Step 2.3

Evaluate $\frac{d}{d x} [2 x y^{2}]$ .

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Step 2.3.1

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

$3 x^{2} - 3 (x^{2} y' + 2 y x) + 2 \frac{d}{d x} [x y^{2}]$

Step 2.3.2

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 $f (x) = x$ and $g (x) = y^{2}$ .

$3 x^{2} - 3 (x^{2} y' + 2 y x) + 2 (x \frac{d}{d x} [y^{2}] + y^{2} \frac{d}{d x} [x])$

Step 2.3.3

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

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Step 2.3.3.1

To apply the Chain Rule, set $u$ as $y$ .

$3 x^{2} - 3 (x^{2} y' + 2 y x) + 2 (x (\frac{d}{d u} [u^{2}] \frac{d}{d x} [y]) + y^{2} \frac{d}{d x} [x])$

Step 2.3.3.2

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

$3 x^{2} - 3 (x^{2} y' + 2 y x) + 2 (x (2 u \frac{d}{d x} [y]) + y^{2} \frac{d}{d x} [x])$

Step 2.3.3.3

Replace all occurrences of $u$ with $y$ .

$3 x^{2} - 3 (x^{2} y' + 2 y x) + 2 (x (2 y \frac{d}{d x} [y]) + y^{2} \frac{d}{d x} [x])$

Step 2.3.4

Rewrite $\frac{d}{d x} [y]$ as $y'$ .

$3 x^{2} - 3 (x^{2} y' + 2 y x) + 2 (x (2 y y') + y^{2} \frac{d}{d x} [x])$

Step 2.3.5

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

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

Step 2.3.6

Move $2$ to the left of $x$ .

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

Step 2.3.7

Multiply $y^{2}$ by $1$ .

$3 x^{2} - 3 (x^{2} y' + 2 y x) + 2 (2 x y y' + y^{2})$

Step 2.4

Simplify.

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Step 2.4.1

Apply the distributive property.

$3 x^{2} - 3 (x^{2} y') - 3 (2 y x) + 2 (2 x y y' + y^{2})$

Step 2.4.2

Apply the distributive property.

$3 x^{2} - 3 (x^{2} y') - 3 (2 y x) + 2 (2 x y y') + 2 y^{2}$

Step 2.4.3

Combine terms.

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Step 2.4.3.1

Multiply $2$ by $- 3$ .

$3 x^{2} - 3 x^{2} y' - 6 (y x) + 2 (2 x y y') + 2 y^{2}$

Step 2.4.3.2

Multiply $2$ by $2$ .

$3 x^{2} - 3 x^{2} y' - 6 y x + 4 x y y' + 2 y^{2}$

Step 2.4.4

Reorder terms.

$3 x^{2} + 2 y^{2} - 3 x^{2} y' - 6 x y + 4 x y y'$

Step 3

Since $12$ is constant with respect to $x$ , the derivative of $12$ with respect to $x$ is $0$ .

$0$

Step 4

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

$3 x^{2} + 2 y^{2} - 3 x^{2} y' - 6 x y + 4 x y y' = 0$

Step 5

Solve for $y'$ .

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Step 5.1

Move all terms not containing $y'$ to the right side of the equation.

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Step 5.1.1

Subtract $3 x^{2}$ from both sides of the equation.

$2 y^{2} - 3 x^{2} y' - 6 x y + 4 x y y' = - 3 x^{2}$

Step 5.1.2

Subtract $2 y^{2}$ from both sides of the equation.

$- 3 x^{2} y' - 6 x y + 4 x y y' = - 3 x^{2} - 2 y^{2}$

Step 5.1.3

Add $6 x y$ to both sides of the equation.

$- 3 x^{2} y' + 4 x y y' = - 3 x^{2} - 2 y^{2} + 6 x y$

Step 5.2

Factor $x y'$ out of $- 3 x^{2} y' + 4 x y y'$ .

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Step 5.2.1

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

$x y' (- 3 x) + 4 x y y' = - 3 x^{2} - 2 y^{2} + 6 x y$

Step 5.2.2

Factor $x y'$ out of $4 x y y'$ .

$x y' (- 3 x) + x y' (4 y) = - 3 x^{2} - 2 y^{2} + 6 x y$

Step 5.2.3

Factor $x y'$ out of $x y' (- 3 x) + x y' (4 y)$ .

$x y' (- 3 x + 4 y) = - 3 x^{2} - 2 y^{2} + 6 x y$

Step 5.3

Divide each term in $x y' (- 3 x + 4 y) = - 3 x^{2} - 2 y^{2} + 6 x y$ by $x (- 3 x + 4 y)$ and simplify.

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Step 5.3.1

Divide each term in $x y' (- 3 x + 4 y) = - 3 x^{2} - 2 y^{2} + 6 x y$ by $x (- 3 x + 4 y)$ .

$\frac{x y' (- 3 x + 4 y)}{x (- 3 x + 4 y)} = \frac{- 3 x^{2}}{x (- 3 x + 4 y)} + \frac{- 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 x y}{x (- 3 x + 4 y)}$

Step 5.3.2

Simplify the left side.

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Step 5.3.2.1

Cancel the common factor of $x$ .

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Step 5.3.2.1.1

Cancel the common factor.

$\frac{x y' (- 3 x + 4 y)}{x (- 3 x + 4 y)} = \frac{- 3 x^{2}}{x (- 3 x + 4 y)} + \frac{- 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 x y}{x (- 3 x + 4 y)}$

Step 5.3.2.1.2

Rewrite the expression.

$\frac{y' (- 3 x + 4 y)}{- 3 x + 4 y} = \frac{- 3 x^{2}}{x (- 3 x + 4 y)} + \frac{- 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 x y}{x (- 3 x + 4 y)}$

Step 5.3.2.2

Cancel the common factor of $- 3 x + 4 y$ .

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Step 5.3.2.2.1

Cancel the common factor.

$\frac{y' (- 3 x + 4 y)}{- 3 x + 4 y} = \frac{- 3 x^{2}}{x (- 3 x + 4 y)} + \frac{- 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 x y}{x (- 3 x + 4 y)}$

Step 5.3.2.2.2

Divide $y'$ by $1$ .

$y' = \frac{- 3 x^{2}}{x (- 3 x + 4 y)} + \frac{- 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 x y}{x (- 3 x + 4 y)}$

Step 5.3.3

Simplify the right side.

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Step 5.3.3.1

Simplify each term.

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Step 5.3.3.1.1

Cancel the common factor of $x^{2}$ and $x$ .

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Step 5.3.3.1.1.1

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

$y' = \frac{x (- 3 x)}{x (- 3 x + 4 y)} + \frac{- 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 x y}{x (- 3 x + 4 y)}$

Step 5.3.3.1.1.2

Cancel the common factors.

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Step 5.3.3.1.1.2.1

Cancel the common factor.

$y' = \frac{x (- 3 x)}{x (- 3 x + 4 y)} + \frac{- 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 x y}{x (- 3 x + 4 y)}$

Step 5.3.3.1.1.2.2

Rewrite the expression.

$y' = \frac{- 3 x}{- 3 x + 4 y} + \frac{- 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 x y}{x (- 3 x + 4 y)}$

Step 5.3.3.1.2

Move the negative in front of the fraction.

$y' = - \frac{3 x}{- 3 x + 4 y} + \frac{- 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 x y}{x (- 3 x + 4 y)}$

Step 5.3.3.1.3

Move the negative in front of the fraction.

$y' = - \frac{3 x}{- 3 x + 4 y} - \frac{2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 x y}{x (- 3 x + 4 y)}$

Step 5.3.3.1.4

Cancel the common factor of $x$ .

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Step 5.3.3.1.4.1

Cancel the common factor.

$y' = - \frac{3 x}{- 3 x + 4 y} - \frac{2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 x y}{x (- 3 x + 4 y)}$

Step 5.3.3.1.4.2

Rewrite the expression.

$y' = - \frac{3 x}{- 3 x + 4 y} - \frac{2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 y}{- 3 x + 4 y}$

Step 5.3.3.2

To write $- \frac{3 x}{- 3 x + 4 y}$ as a fraction with a common denominator, multiply by $\frac{x}{x}$ .

$y' = - \frac{3 x}{- 3 x + 4 y} \cdot \frac{x}{x} - \frac{2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 y}{- 3 x + 4 y}$

Step 5.3.3.3

Write each expression with a common denominator of $(- 3 x + 4 y) x$ , by multiplying each by an appropriate factor of $1$ .

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Step 5.3.3.3.1

Multiply $\frac{3 x}{- 3 x + 4 y}$ by $\frac{x}{x}$ .

$y' = - \frac{3 x \cdot x}{(- 3 x + 4 y) x} - \frac{2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 y}{- 3 x + 4 y}$

Step 5.3.3.3.2

Reorder the factors of $(- 3 x + 4 y) x$ .

$y' = - \frac{3 x \cdot x}{x (- 3 x + 4 y)} - \frac{2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 y}{- 3 x + 4 y}$

Step 5.3.3.4

Combine the numerators over the common denominator.

$y' = \frac{- 3 x \cdot x - 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 y}{- 3 x + 4 y}$

Step 5.3.3.5

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

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Step 5.3.3.5.1

Move $x$ .

$y' = \frac{- 3 (x \cdot x) - 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 y}{- 3 x + 4 y}$

Step 5.3.3.5.2

Multiply $x$ by $x$ .

$y' = \frac{- 3 x^{2} - 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 y}{- 3 x + 4 y}$

Step 5.3.3.6

To write $\frac{6 y}{- 3 x + 4 y}$ as a fraction with a common denominator, multiply by $\frac{x}{x}$ .

$y' = \frac{- 3 x^{2} - 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 y}{- 3 x + 4 y} \cdot \frac{x}{x}$

Step 5.3.3.7

Write each expression with a common denominator of $x (- 3 x + 4 y)$ , by multiplying each by an appropriate factor of $1$ .

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Step 5.3.3.7.1

Multiply $\frac{6 y}{- 3 x + 4 y}$ by $\frac{x}{x}$ .

$y' = \frac{- 3 x^{2} - 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 y x}{(- 3 x + 4 y) x}$

Step 5.3.3.7.2

Reorder the factors of $(- 3 x + 4 y) x$ .

$y' = \frac{- 3 x^{2} - 2 y^{2}}{x (- 3 x + 4 y)} + \frac{6 y x}{x (- 3 x + 4 y)}$

Step 5.3.3.8

Combine the numerators over the common denominator.

$y' = \frac{- 3 x^{2} - 2 y^{2} + 6 y x}{x (- 3 x + 4 y)}$

Step 5.3.3.9

Factor $- 1$ out of $- 3 x^{2}$ .

$y' = \frac{- (3 x^{2}) - 2 y^{2} + 6 y x}{x (- 3 x + 4 y)}$

Step 5.3.3.10

Factor $- 1$ out of $- 2 y^{2}$ .

$y' = \frac{- (3 x^{2}) - (2 y^{2}) + 6 y x}{x (- 3 x + 4 y)}$

Step 5.3.3.11

Factor $- 1$ out of $- (3 x^{2}) - (2 y^{2})$ .

$y' = \frac{- (3 x^{2} + 2 y^{2}) + 6 y x}{x (- 3 x + 4 y)}$

Step 5.3.3.12

Factor $- 1$ out of $6 y x$ .

$y' = \frac{- (3 x^{2} + 2 y^{2}) - (- 6 y x)}{x (- 3 x + 4 y)}$

Step 5.3.3.13

Factor $- 1$ out of $- (3 x^{2} + 2 y^{2}) - (- 6 y x)$ .

$y' = \frac{- (3 x^{2} + 2 y^{2} - 6 y x)}{x (- 3 x + 4 y)}$

Step 5.3.3.14

Rewrite $- (3 x^{2} + 2 y^{2} - 6 y x)$ as $- 1 (3 x^{2} + 2 y^{2} - 6 y x)$ .

$y' = \frac{- 1 (3 x^{2} + 2 y^{2} - 6 y x)}{x (- 3 x + 4 y)}$

Step 5.3.3.15

Factor $- 1$ out of $- 3 x$ .

$y' = \frac{- 1 (3 x^{2} + 2 y^{2} - 6 y x)}{x (- (3 x) + 4 y)}$

Step 5.3.3.16

Factor $- 1$ out of $4 y$ .

$y' = \frac{- 1 (3 x^{2} + 2 y^{2} - 6 y x)}{x (- (3 x) - (- 4 y))}$

Step 5.3.3.17

Factor $- 1$ out of $- (3 x) - (- 4 y)$ .

$y' = \frac{- 1 (3 x^{2} + 2 y^{2} - 6 y x)}{x (- (3 x - 4 y))}$

Step 5.3.3.18

Rewrite $- (3 x - 4 y)$ as $- 1 (3 x - 4 y)$ .

$y' = \frac{- 1 (3 x^{2} + 2 y^{2} - 6 y x)}{x (- 1 (3 x - 4 y))}$

Step 5.3.3.19

Cancel the common factor.

$y' = \frac{- 1 (3 x^{2} + 2 y^{2} - 6 y x)}{x (- 1 (3 x - 4 y))}$

Step 5.3.3.20

Rewrite the expression.

$y' = \frac{3 x^{2} + 2 y^{2} - 6 y x}{x (3 x - 4 y)}$

Step 6

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

$\frac{d y}{d x} = \frac{3 x^{2} + 2 y^{2} - 6 y x}{x (3 x - 4 y)}$