Calculus Examples

$y = \sqrt{x} (3 x - 1)$

Step 1

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

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

Step 2

Differentiate both sides of the equation.

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

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 $f (x) = x^{\frac{1}{2}}$ and $g (x) = 3 x - 1$ .

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

Step 4.2

Differentiate.

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Step 4.2.1

By the Sum Rule, the derivative of $3 x - 1$ with respect to $x$ is $\frac{d}{d x} [3 x] + \frac{d}{d x} [- 1]$ .

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

Step 4.2.2

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

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

Step 4.2.3

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

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

Step 4.2.4

Multiply $3$ by $1$ .

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

Step 4.2.5

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

$x^{\frac{1}{2}} (3 + 0) + (3 x - 1) \frac{d}{d x} [x^{\frac{1}{2}}]$

Step 4.2.6

Simplify the expression.

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Step 4.2.6.1

Add $3$ and $0$ .

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

Step 4.2.6.2

Move $3$ to the left of $x^{\frac{1}{2}}$ .

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

Step 4.2.7

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

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

Step 4.3

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

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

Step 4.4

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

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

Step 4.5

Combine the numerators over the common denominator.

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

Step 4.6

Simplify the numerator.

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Step 4.6.1

Multiply $- 1$ by $2$ .

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

Step 4.6.2

Subtract $2$ from $1$ .

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

Step 4.7

Move the negative in front of the fraction.

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

Step 4.8

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

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

Step 4.9

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

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

Step 4.10

Simplify.

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Step 4.10.1

Apply the distributive property.

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

Step 4.10.2

Combine terms.

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Step 4.10.2.1

Combine $3$ and $\frac{1}{2 x^{\frac{1}{2}}}$ .

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

Step 4.10.2.2

Combine $x$ and $\frac{3}{2 x^{\frac{1}{2}}}$ .

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

Step 4.10.2.3

Move $3$ to the left of $x$ .

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

Step 4.10.2.4

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

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

Step 4.10.2.5

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

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Step 4.10.2.5.1

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

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

Step 4.10.2.5.2

Multiply $x^{- \frac{1}{2}}$ by $x$ .

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Step 4.10.2.5.2.1

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

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

Step 4.10.2.5.2.2

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

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

Step 4.10.2.5.3

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

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

Step 4.10.2.5.4

Combine the numerators over the common denominator.

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

Step 4.10.2.5.5

Add $- 1$ and $2$ .

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

Step 4.10.2.6

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

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

Step 4.10.2.7

To write $3 x^{\frac{1}{2}}$ as a fraction with a common denominator, multiply by $\frac{2}{2}$ .

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

Step 4.10.2.8

Combine $3 x^{\frac{1}{2}}$ and $\frac{2}{2}$ .

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

Step 4.10.2.9

Combine the numerators over the common denominator.

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

Step 4.10.2.10

Multiply $2$ by $3$ .

$\frac{6 x^{\frac{1}{2}} + 3 x^{\frac{1}{2}}}{2} - \frac{1}{2 x^{\frac{1}{2}}}$

Step 4.10.2.11

Add $6 x^{\frac{1}{2}}$ and $3 x^{\frac{1}{2}}$ .

$\frac{9 x^{\frac{1}{2}}}{2} - \frac{1}{2 x^{\frac{1}{2}}}$

Step 5

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

$y' = \frac{9 x^{\frac{1}{2}}}{2} - \frac{1}{2 x^{\frac{1}{2}}}$

Step 6

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

$\frac{d y}{d x} = \frac{9 x^{\frac{1}{2}}}{2} - \frac{1}{2 x^{\frac{1}{2}}}$