Calculus Examples

$lim_{x \to 2} \frac{\sqrt{2 x} - \sqrt{6 - x}}{4 - x^{2}}$

Step 1

Apply L'Hospital's rule.

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Step 1.1

Evaluate the limit of the numerator and the limit of the denominator.

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Step 1.1.1

Take the limit of the numerator and the limit of the denominator.

$\frac{lim_{x \to 2} \sqrt{2 x} - \sqrt{6 - x}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2

Evaluate the limit of the numerator.

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Step 1.1.2.1

Split the limit using the Sum of Limits Rule on the limit as $x$ approaches $2$ .

$\frac{lim_{x \to 2} \sqrt{2 x} - lim_{x \to 2} \sqrt{6 - x}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.2

Move the limit under the radical sign.

$\frac{\sqrt{lim_{x \to 2} 2 x} - lim_{x \to 2} \sqrt{6 - x}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.3

Move the term $2$ outside of the limit because it is constant with respect to $x$ .

$\frac{\sqrt{2 lim_{x \to 2} x} - lim_{x \to 2} \sqrt{6 - x}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.4

Move the limit under the radical sign.

$\frac{\sqrt{2 lim_{x \to 2} x} - \sqrt{lim_{x \to 2} 6 - x}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.5

Split the limit using the Sum of Limits Rule on the limit as $x$ approaches $2$ .

$\frac{\sqrt{2 lim_{x \to 2} x} - \sqrt{lim_{x \to 2} 6 - lim_{x \to 2} x}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.6

Evaluate the limit of $6$ which is constant as $x$ approaches $2$ .

$\frac{\sqrt{2 lim_{x \to 2} x} - \sqrt{6 - lim_{x \to 2} x}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.7

Evaluate the limits by plugging in $2$ for all occurrences of $x$ .

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Step 1.1.2.7.1

Evaluate the limit of $x$ by plugging in $2$ for $x$ .

$\frac{\sqrt{2 \cdot 2} - \sqrt{6 - lim_{x \to 2} x}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.7.2

Evaluate the limit of $x$ by plugging in $2$ for $x$ .

$\frac{\sqrt{2 \cdot 2} - \sqrt{6 - 2}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.8

Simplify the answer.

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Step 1.1.2.8.1

Simplify each term.

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Step 1.1.2.8.1.1

Multiply $2$ by $2$ .

$\frac{\sqrt{4} - \sqrt{6 - 2}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.8.1.2

Rewrite $4$ as $2^{2}$ .

$\frac{\sqrt{2^{2}} - \sqrt{6 - 2}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.8.1.3

Pull terms out from under the radical, assuming positive real numbers.

$\frac{2 - \sqrt{6 - 2}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.8.1.4

Subtract $2$ from $6$ .

$\frac{2 - \sqrt{4}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.8.1.5

Rewrite $4$ as $2^{2}$ .

$\frac{2 - \sqrt{2^{2}}}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.8.1.6

Pull terms out from under the radical, assuming positive real numbers.

$\frac{2 - 1 \cdot 2}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.8.1.7

Multiply $- 1$ by $2$ .

$\frac{2 - 2}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.2.8.2

Subtract $2$ from $2$ .

$\frac{0}{lim_{x \to 2} 4 - x^{2}}$

Step 1.1.3

Evaluate the limit of the denominator.

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Step 1.1.3.1

Evaluate the limit.

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Step 1.1.3.1.1

Split the limit using the Sum of Limits Rule on the limit as $x$ approaches $2$ .

$\frac{0}{lim_{x \to 2} 4 - lim_{x \to 2} x^{2}}$

Step 1.1.3.1.2

Evaluate the limit of $4$ which is constant as $x$ approaches $2$ .

$\frac{0}{4 - lim_{x \to 2} x^{2}}$

Step 1.1.3.1.3

Move the exponent $2$ from $x^{2}$ outside the limit using the Limits Power Rule.

$\frac{0}{4 - {(lim_{x \to 2} x)}^{2}}$

Step 1.1.3.2

Evaluate the limit of $x$ by plugging in $2$ for $x$ .

$\frac{0}{4 - 2^{2}}$

Step 1.1.3.3

Simplify the answer.

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Step 1.1.3.3.1

Simplify each term.

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Step 1.1.3.3.1.1

Raise $2$ to the power of $2$ .

$\frac{0}{4 - 1 \cdot 4}$

Step 1.1.3.3.1.2

Multiply $- 1$ by $4$ .

$\frac{0}{4 - 4}$

Step 1.1.3.3.2

Subtract $4$ from $4$ .

$\frac{0}{0}$

Step 1.1.3.3.3

The expression contains a division by $0$ . The expression is undefined.

Undefined

$\frac{0}{0}$

Step 1.1.3.4

The expression contains a division by $0$ . The expression is undefined.

Undefined

$\frac{0}{0}$

Step 1.1.4

The expression contains a division by $0$ . The expression is undefined.

Undefined

$\frac{0}{0}$

Step 1.2

Since $\frac{0}{0}$ is of indeterminate form, apply L'Hospital's Rule. L'Hospital's Rule states that the limit of a quotient of functions is equal to the limit of the quotient of their derivatives.

$lim_{x \to 2} \frac{\sqrt{2 x} - \sqrt{6 - x}}{4 - x^{2}} = lim_{x \to 2} \frac{\frac{d}{d x} [\sqrt{2 x} - \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3

Find the derivative of the numerator and denominator.

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Step 1.3.1

Differentiate the numerator and denominator.

$lim_{x \to 2} \frac{\frac{d}{d x} [\sqrt{2 x} - \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.2

By the Sum Rule, the derivative of $\sqrt{2 x} - \sqrt{6 - x}$ with respect to $x$ is $\frac{d}{d x} [\sqrt{2 x}] + \frac{d}{d x} [- \sqrt{6 - x}]$ .

$lim_{x \to 2} \frac{\frac{d}{d x} [\sqrt{2 x}] + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3

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

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Step 1.3.3.1

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

$lim_{x \to 2} \frac{\frac{d}{d x} [{(2 x)}^{\frac{1}{2}}] + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.2

Factor $2$ out of $2 x$ .

$lim_{x \to 2} \frac{\frac{d}{d x} [{(2 (x))}^{\frac{1}{2}}] + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.3

Apply the product rule to $2 (x)$ .

$lim_{x \to 2} \frac{\frac{d}{d x} [2^{\frac{1}{2}} x^{\frac{1}{2}}] + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.4

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

$lim_{x \to 2} \frac{2^{\frac{1}{2}} \frac{d}{d x} [x^{\frac{1}{2}}] + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.5

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

$lim_{x \to 2} \frac{2^{\frac{1}{2}} (\frac{1}{2} x^{\frac{1}{2} - 1}) + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.6

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

$lim_{x \to 2} \frac{2^{\frac{1}{2}} (\frac{1}{2} x^{\frac{1}{2} - 1 \cdot \frac{2}{2}}) + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.7

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

$lim_{x \to 2} \frac{2^{\frac{1}{2}} (\frac{1}{2} x^{\frac{1}{2} + \frac{- 1 \cdot 2}{2}}) + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.8

Combine the numerators over the common denominator.

$lim_{x \to 2} \frac{2^{\frac{1}{2}} (\frac{1}{2} x^{\frac{1 - 1 \cdot 2}{2}}) + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.9

Simplify the numerator.

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Step 1.3.3.9.1

Multiply $- 1$ by $2$ .

$lim_{x \to 2} \frac{2^{\frac{1}{2}} (\frac{1}{2} x^{\frac{1 - 2}{2}}) + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.9.2

Subtract $2$ from $1$ .

$lim_{x \to 2} \frac{2^{\frac{1}{2}} (\frac{1}{2} x^{\frac{- 1}{2}}) + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.10

Move the negative in front of the fraction.

$lim_{x \to 2} \frac{2^{\frac{1}{2}} (\frac{1}{2} x^{- \frac{1}{2}}) + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.11

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

$lim_{x \to 2} \frac{2^{\frac{1}{2}} \frac{x^{- \frac{1}{2}}}{2} + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.12

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

$lim_{x \to 2} \frac{\frac{2^{\frac{1}{2}} x^{- \frac{1}{2}}}{2} + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.13

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

$lim_{x \to 2} \frac{\frac{x^{- \frac{1}{2}}}{2 \cdot 2^{- \frac{1}{2}}} + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.14

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

$lim_{x \to 2} \frac{\frac{1}{2 \cdot 2^{- \frac{1}{2}} x^{\frac{1}{2}}} + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.15

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

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Step 1.3.3.15.1

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

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Step 1.3.3.15.1.1

Raise $2$ to the power of $1$ .

$lim_{x \to 2} \frac{\frac{1}{2^{1} \cdot 2^{- \frac{1}{2}} x^{\frac{1}{2}}} + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.15.1.2

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

$lim_{x \to 2} \frac{\frac{1}{2^{1 - \frac{1}{2}} x^{\frac{1}{2}}} + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.15.2

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

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{2}{2} - \frac{1}{2}} x^{\frac{1}{2}}} + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.15.3

Combine the numerators over the common denominator.

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{2 - 1}{2}} x^{\frac{1}{2}}} + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.3.15.4

Subtract $1$ from $2$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} + \frac{d}{d x} [- \sqrt{6 - x}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4

Evaluate $\frac{d}{d x} [- \sqrt{6 - x}]$ .

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Step 1.3.4.1

Use $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$ to rewrite $\sqrt{6 - x}$ as ${(6 - x)}^{\frac{1}{2}}$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} + \frac{d}{d x} [- {(6 - x)}^{\frac{1}{2}}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.2

Since $- 1$ is constant with respect to $x$ , the derivative of $- {(6 - x)}^{\frac{1}{2}}$ with respect to $x$ is $- \frac{d}{d x} [{(6 - x)}^{\frac{1}{2}}]$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - \frac{d}{d x} [{(6 - x)}^{\frac{1}{2}}]}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.3

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 $g (x) = 6 - x$ .

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Step 1.3.4.3.1

To apply the Chain Rule, set $u$ as $6 - x$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{d}{d u} [u^{\frac{1}{2}}] \frac{d}{d x} [6 - x])}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.3.2

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

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} u^{\frac{1}{2} - 1} \frac{d}{d x} [6 - x])}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.3.3

Replace all occurrences of $u$ with $6 - x$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} {(6 - x)}^{\frac{1}{2} - 1} \frac{d}{d x} [6 - x])}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.4

By the Sum Rule, the derivative of $6 - x$ with respect to $x$ is $\frac{d}{d x} [6] + \frac{d}{d x} [- x]$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} {(6 - x)}^{\frac{1}{2} - 1} (\frac{d}{d x} [6] + \frac{d}{d x} [- x]))}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.5

Since $6$ is constant with respect to $x$ , the derivative of $6$ with respect to $x$ is $0$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} {(6 - x)}^{\frac{1}{2} - 1} (0 + \frac{d}{d x} [- x]))}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.6

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

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} {(6 - x)}^{\frac{1}{2} - 1} (0 - \frac{d}{d x} [x]))}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.7

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

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} {(6 - x)}^{\frac{1}{2} - 1} (0 - 1 \cdot 1))}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.8

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

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} {(6 - x)}^{\frac{1}{2} - 1 \cdot \frac{2}{2}} (0 - 1 \cdot 1))}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.9

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

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} {(6 - x)}^{\frac{1}{2} + \frac{- 1 \cdot 2}{2}} (0 - 1 \cdot 1))}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.10

Combine the numerators over the common denominator.

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} {(6 - x)}^{\frac{1 - 1 \cdot 2}{2}} (0 - 1 \cdot 1))}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.11

Simplify the numerator.

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Step 1.3.4.11.1

Multiply $- 1$ by $2$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} {(6 - x)}^{\frac{1 - 2}{2}} (0 - 1 \cdot 1))}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.11.2

Subtract $2$ from $1$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} {(6 - x)}^{\frac{- 1}{2}} (0 - 1 \cdot 1))}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.12

Move the negative in front of the fraction.

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} {(6 - x)}^{- \frac{1}{2}} (0 - 1 \cdot 1))}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.13

Multiply $- 1$ by $1$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} {(6 - x)}^{- \frac{1}{2}} (0 - 1))}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.14

Subtract $1$ from $0$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{1}{2} {(6 - x)}^{- \frac{1}{2}} \cdot - 1)}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.15

Combine $\frac{1}{2}$ and ${(6 - x)}^{- \frac{1}{2}}$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - (\frac{{(6 - x)}^{- \frac{1}{2}}}{2} \cdot - 1)}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.16

Combine $\frac{{(6 - x)}^{- \frac{1}{2}}}{2}$ and $- 1$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - \frac{{(6 - x)}^{- \frac{1}{2}} \cdot - 1}{2}}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.17

Move $- 1$ to the left of ${(6 - x)}^{- \frac{1}{2}}$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - \frac{- 1 \cdot {(6 - x)}^{- \frac{1}{2}}}{2}}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.18

Rewrite $- 1 {(6 - x)}^{- \frac{1}{2}}$ as $- {(6 - x)}^{- \frac{1}{2}}$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - \frac{- {(6 - x)}^{- \frac{1}{2}}}{2}}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.19

Move ${(6 - x)}^{- \frac{1}{2}}$ to the denominator using the negative exponent rule $b^{- n} = \frac{1}{b^{n}}$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - \frac{- 1}{2 {(6 - x)}^{\frac{1}{2}}}}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.20

Move the negative in front of the fraction.

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} - - \frac{1}{2 {(6 - x)}^{\frac{1}{2}}}}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.21

Multiply $- 1$ by $- 1$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} + 1 \frac{1}{2 {(6 - x)}^{\frac{1}{2}}}}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.4.22

Multiply $\frac{1}{2 {(6 - x)}^{\frac{1}{2}}}$ by $1$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} + \frac{1}{2 {(6 - x)}^{\frac{1}{2}}}}{\frac{d}{d x} [4 - x^{2}]}$

Step 1.3.5

By the Sum Rule, the derivative of $4 - x^{2}$ with respect to $x$ is $\frac{d}{d x} [4] + \frac{d}{d x} [- x^{2}]$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} + \frac{1}{2 {(6 - x)}^{\frac{1}{2}}}}{\frac{d}{d x} [4] + \frac{d}{d x} [- x^{2}]}$

Step 1.3.6

Since $4$ is constant with respect to $x$ , the derivative of $4$ with respect to $x$ is $0$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} + \frac{1}{2 {(6 - x)}^{\frac{1}{2}}}}{0 + \frac{d}{d x} [- x^{2}]}$

Step 1.3.7

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

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Step 1.3.7.1

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

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} + \frac{1}{2 {(6 - x)}^{\frac{1}{2}}}}{0 - \frac{d}{d x} [x^{2}]}$

Step 1.3.7.2

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

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} + \frac{1}{2 {(6 - x)}^{\frac{1}{2}}}}{0 - (2 x)}$

Step 1.3.7.3

Multiply $2$ by $- 1$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} + \frac{1}{2 {(6 - x)}^{\frac{1}{2}}}}{0 - 2 x}$

Step 1.3.8

Subtract $2 x$ from $0$ .

$lim_{x \to 2} \frac{\frac{1}{2^{\frac{1}{2}} x^{\frac{1}{2}}} + \frac{1}{2 {(6 - x)}^{\frac{1}{2}}}}{- 2 x}$

Step 1.4

Convert fractional exponents to radicals.

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Step 1.4.1

Rewrite $2^{\frac{1}{2}}$ as $\sqrt{2}$ .

$lim_{x \to 2} \frac{\frac{1}{\sqrt{2} x^{\frac{1}{2}}} + \frac{1}{2 {(6 - x)}^{\frac{1}{2}}}}{- 2 x}$

Step 1.4.2

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

$lim_{x \to 2} \frac{\frac{1}{\sqrt{2} \sqrt{x}} + \frac{1}{2 {(6 - x)}^{\frac{1}{2}}}}{- 2 x}$

Step 1.4.3

Rewrite ${(6 - x)}^{\frac{1}{2}}$ as $\sqrt{6 - x}$ .

$lim_{x \to 2} \frac{\frac{1}{\sqrt{2} \sqrt{x}} + \frac{1}{2 \sqrt{6 - x}}}{- 2 x}$

Step 1.5

Combine using the product rule for radicals.

$lim_{x \to 2} \frac{\frac{1}{\sqrt{2 x}} + \frac{1}{2 \sqrt{6 - x}}}{- 2 x}$

Step 1.6

Combine terms.

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Step 1.6.1

To write $\frac{1}{\sqrt{2 x}}$ as a fraction with a common denominator, multiply by $\frac{2 \sqrt{6 - x}}{2 \sqrt{6 - x}}$ .

$lim_{x \to 2} \frac{\frac{1}{\sqrt{2 x}} \cdot \frac{2 \sqrt{6 - x}}{2 \sqrt{6 - x}} + \frac{1}{2 \sqrt{6 - x}}}{- 2 x}$

Step 1.6.2

To write $\frac{1}{2 \sqrt{6 - x}}$ as a fraction with a common denominator, multiply by $\frac{\sqrt{2 x}}{\sqrt{2 x}}$ .

$lim_{x \to 2} \frac{\frac{1}{\sqrt{2 x}} \cdot \frac{2 \sqrt{6 - x}}{2 \sqrt{6 - x}} + \frac{1}{2 \sqrt{6 - x}} \cdot \frac{\sqrt{2 x}}{\sqrt{2 x}}}{- 2 x}$

Step 1.6.3

Write each expression with a common denominator of $\sqrt{2 x} \cdot 2 \sqrt{6 - x}$ , by multiplying each by an appropriate factor of $1$ .

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Step 1.6.3.1

Multiply $\frac{1}{\sqrt{2 x}}$ by $\frac{2 \sqrt{6 - x}}{2 \sqrt{6 - x}}$ .

$lim_{x \to 2} \frac{\frac{2 \sqrt{6 - x}}{\sqrt{2 x} (2 \sqrt{6 - x})} + \frac{1}{2 \sqrt{6 - x}} \cdot \frac{\sqrt{2 x}}{\sqrt{2 x}}}{- 2 x}$

Step 1.6.3.2

Combine using the product rule for radicals.

$lim_{x \to 2} \frac{\frac{2 \sqrt{6 - x}}{2 \sqrt{2 x (6 - x)}} + \frac{1}{2 \sqrt{6 - x}} \cdot \frac{\sqrt{2 x}}{\sqrt{2 x}}}{- 2 x}$

Step 1.6.3.3

Multiply $\frac{1}{2 \sqrt{6 - x}}$ by $\frac{\sqrt{2 x}}{\sqrt{2 x}}$ .

$lim_{x \to 2} \frac{\frac{2 \sqrt{6 - x}}{2 \sqrt{2 x (6 - x)}} + \frac{\sqrt{2 x}}{2 \sqrt{6 - x} \sqrt{2 x}}}{- 2 x}$

Step 1.6.3.4

Combine using the product rule for radicals.

$lim_{x \to 2} \frac{\frac{2 \sqrt{6 - x}}{2 \sqrt{2 x (6 - x)}} + \frac{\sqrt{2 x}}{2 \sqrt{2 x (6 - x)}}}{- 2 x}$

Step 1.6.4

Combine the numerators over the common denominator.

$lim_{x \to 2} \frac{\frac{2 \sqrt{6 - x} + \sqrt{2 x}}{2 \sqrt{2 x (6 - x)}}}{- 2 x}$

Step 2

Evaluate the limit.

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Step 2.1

Move the term $\frac{1}{- 2}$ outside of the limit because it is constant with respect to $x$ .

$\frac{1}{- 2} lim_{x \to 2} \frac{\frac{2 \sqrt{6 - x} + \sqrt{2 x}}{2 \sqrt{2 x (6 - x)}}}{x}$

Step 2.2

Split the limit using the Limits Quotient Rule on the limit as $x$ approaches $2$ .

$\frac{1}{- 2} \cdot \frac{lim_{x \to 2} \frac{2 \sqrt{6 - x} + \sqrt{2 x}}{2 \sqrt{2 x (6 - x)}}}{lim_{x \to 2} x}$

Step 2.3

Move the term $\frac{1}{2}$ outside of the limit because it is constant with respect to $x$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} lim_{x \to 2} \frac{2 \sqrt{6 - x} + \sqrt{2 x}}{\sqrt{2 x (6 - x)}}}{lim_{x \to 2} x}$

Step 2.4

Split the limit using the Limits Quotient Rule on the limit as $x$ approaches $2$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{lim_{x \to 2} 2 \sqrt{6 - x} + \sqrt{2 x}}{lim_{x \to 2} \sqrt{2 x (6 - x)}}}{lim_{x \to 2} x}$

Step 2.5

Split the limit using the Sum of Limits Rule on the limit as $x$ approaches $2$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{lim_{x \to 2} 2 \sqrt{6 - x} + lim_{x \to 2} \sqrt{2 x}}{lim_{x \to 2} \sqrt{2 x (6 - x)}}}{lim_{x \to 2} x}$

Step 2.6

Move the term $2$ outside of the limit because it is constant with respect to $x$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 lim_{x \to 2} \sqrt{6 - x} + lim_{x \to 2} \sqrt{2 x}}{lim_{x \to 2} \sqrt{2 x (6 - x)}}}{lim_{x \to 2} x}$

Step 2.7

Move the limit under the radical sign.

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{lim_{x \to 2} 6 - x} + lim_{x \to 2} \sqrt{2 x}}{lim_{x \to 2} \sqrt{2 x (6 - x)}}}{lim_{x \to 2} x}$

Step 2.8

Split the limit using the Sum of Limits Rule on the limit as $x$ approaches $2$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{lim_{x \to 2} 6 - lim_{x \to 2} x} + lim_{x \to 2} \sqrt{2 x}}{lim_{x \to 2} \sqrt{2 x (6 - x)}}}{lim_{x \to 2} x}$

Step 2.9

Evaluate the limit of $6$ which is constant as $x$ approaches $2$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - lim_{x \to 2} x} + lim_{x \to 2} \sqrt{2 x}}{lim_{x \to 2} \sqrt{2 x (6 - x)}}}{lim_{x \to 2} x}$

Step 2.10

Move the limit under the radical sign.

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - lim_{x \to 2} x} + \sqrt{lim_{x \to 2} 2 x}}{lim_{x \to 2} \sqrt{2 x (6 - x)}}}{lim_{x \to 2} x}$

Step 2.11

Move the term $2$ outside of the limit because it is constant with respect to $x$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - lim_{x \to 2} x} + \sqrt{2 lim_{x \to 2} x}}{lim_{x \to 2} \sqrt{2 x (6 - x)}}}{lim_{x \to 2} x}$

Step 2.12

Move the limit under the radical sign.

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - lim_{x \to 2} x} + \sqrt{2 lim_{x \to 2} x}}{\sqrt{lim_{x \to 2} 2 x (6 - x)}}}{lim_{x \to 2} x}$

Step 2.13

Move the term $2$ outside of the limit because it is constant with respect to $x$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - lim_{x \to 2} x} + \sqrt{2 lim_{x \to 2} x}}{\sqrt{2 lim_{x \to 2} x (6 - x)}}}{lim_{x \to 2} x}$

Step 2.14

Split the limit using the Product of Limits Rule on the limit as $x$ approaches $2$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - lim_{x \to 2} x} + \sqrt{2 lim_{x \to 2} x}}{\sqrt{2 lim_{x \to 2} x \cdot lim_{x \to 2} 6 - x}}}{lim_{x \to 2} x}$

Step 2.15

Split the limit using the Sum of Limits Rule on the limit as $x$ approaches $2$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - lim_{x \to 2} x} + \sqrt{2 lim_{x \to 2} x}}{\sqrt{2 lim_{x \to 2} x \cdot (lim_{x \to 2} 6 - lim_{x \to 2} x)}}}{lim_{x \to 2} x}$

Step 2.16

Evaluate the limit of $6$ which is constant as $x$ approaches $2$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - lim_{x \to 2} x} + \sqrt{2 lim_{x \to 2} x}}{\sqrt{2 lim_{x \to 2} x \cdot (6 - lim_{x \to 2} x)}}}{lim_{x \to 2} x}$

Step 3

Evaluate the limits by plugging in $2$ for all occurrences of $x$ .

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Step 3.1

Evaluate the limit of $x$ by plugging in $2$ for $x$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - 2} + \sqrt{2 lim_{x \to 2} x}}{\sqrt{2 lim_{x \to 2} x \cdot (6 - lim_{x \to 2} x)}}}{lim_{x \to 2} x}$

Step 3.2

Evaluate the limit of $x$ by plugging in $2$ for $x$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - 2} + \sqrt{2 \cdot 2}}{\sqrt{2 lim_{x \to 2} x \cdot (6 - lim_{x \to 2} x)}}}{lim_{x \to 2} x}$

Step 3.3

Evaluate the limit of $x$ by plugging in $2$ for $x$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - 2} + \sqrt{2 \cdot 2}}{\sqrt{2 \cdot 2 \cdot (6 - lim_{x \to 2} x)}}}{lim_{x \to 2} x}$

Step 3.4

Evaluate the limit of $x$ by plugging in $2$ for $x$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - 2} + \sqrt{2 \cdot 2}}{\sqrt{2 \cdot 2 \cdot (6 - 2)}}}{lim_{x \to 2} x}$

Step 3.5

Evaluate the limit of $x$ by plugging in $2$ for $x$ .

$\frac{1}{- 2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - 2} + \sqrt{2 \cdot 2}}{\sqrt{2 \cdot 2 \cdot (6 - 2)}}}{2}$

Step 4

Simplify the answer.

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Step 4.1

Move the negative in front of the fraction.

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{6 - 2} + \sqrt{2 \cdot 2}}{\sqrt{2 \cdot 2 \cdot (6 - 2)}}}{2}$

Step 4.2

Simplify the numerator.

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Step 4.2.1

Subtract $2$ from $6$ .

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{4} + \sqrt{2 \cdot 2}}{\sqrt{2 \cdot 2 \cdot (6 - 2)}}}{2}$

Step 4.2.2

Rewrite $4$ as $2^{2}$ .

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \sqrt{2^{2}} + \sqrt{2 \cdot 2}}{\sqrt{2 \cdot 2 \cdot (6 - 2)}}}{2}$

Step 4.2.3

Pull terms out from under the radical, assuming positive real numbers.

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{2 \cdot 2 + \sqrt{2 \cdot 2}}{\sqrt{2 \cdot 2 \cdot (6 - 2)}}}{2}$

Step 4.2.4

Multiply $2$ by $2$ .

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{4 + \sqrt{2 \cdot 2}}{\sqrt{2 \cdot 2 \cdot (6 - 2)}}}{2}$

Step 4.2.5

Multiply $2$ by $2$ .

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{4 + \sqrt{4}}{\sqrt{2 \cdot 2 \cdot (6 - 2)}}}{2}$

Step 4.2.6

Rewrite $4$ as $2^{2}$ .

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{4 + \sqrt{2^{2}}}{\sqrt{2 \cdot 2 \cdot (6 - 2)}}}{2}$

Step 4.2.7

Pull terms out from under the radical, assuming positive real numbers.

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{4 + 2}{\sqrt{2 \cdot 2 \cdot (6 - 2)}}}{2}$

Step 4.2.8

Add $4$ and $2$ .

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{6}{\sqrt{2 \cdot 2 \cdot (6 - 2)}}}{2}$

Step 4.3

Simplify the denominator.

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Step 4.3.1

Multiply $2$ by $2$ .

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{6}{\sqrt{4 (6 - 2)}}}{2}$

Step 4.3.2

Subtract $2$ from $6$ .

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{6}{\sqrt{4 \cdot 4}}}{2}$

Step 4.3.3

Multiply $4$ by $4$ .

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{6}{\sqrt{16}}}{2}$

Step 4.3.4

Rewrite $16$ as $4^{2}$ .

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{6}{\sqrt{4^{2}}}}{2}$

Step 4.3.5

Pull terms out from under the radical, assuming positive real numbers.

$- \frac{1}{2} \cdot \frac{\frac{1}{2} \cdot \frac{6}{4}}{2}$

Step 4.4

Multiply $\frac{1}{2}$ by $\frac{6}{4}$ .

$- \frac{1}{2} \cdot \frac{\frac{6}{2 \cdot 4}}{2}$

Step 4.5

Multiply $2$ by $4$ .

$- \frac{1}{2} \cdot \frac{\frac{6}{8}}{2}$

Step 4.6

Cancel the common factor of $6$ and $8$ .

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Step 4.6.1

Factor $2$ out of $6$ .

$- \frac{1}{2} \cdot \frac{\frac{2 (3)}{8}}{2}$

Step 4.6.2

Cancel the common factors.

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Step 4.6.2.1

Factor $2$ out of $8$ .

$- \frac{1}{2} \cdot \frac{\frac{2 \cdot 3}{2 \cdot 4}}{2}$

Step 4.6.2.2

Cancel the common factor.

$- \frac{1}{2} \cdot \frac{\frac{2 \cdot 3}{2 \cdot 4}}{2}$

Step 4.6.2.3

Rewrite the expression.

$- \frac{1}{2} \cdot \frac{\frac{3}{4}}{2}$

Step 4.7

Multiply the numerator by the reciprocal of the denominator.

$- \frac{1}{2} (\frac{3}{4} \cdot \frac{1}{2})$

Step 4.8

Multiply $\frac{3}{4} \cdot \frac{1}{2}$ .

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Step 4.8.1

Multiply $\frac{3}{4}$ by $\frac{1}{2}$ .

$- \frac{1}{2} \cdot \frac{3}{4 \cdot 2}$

Step 4.8.2

Multiply $4$ by $2$ .

$- \frac{1}{2} \cdot \frac{3}{8}$

Step 4.9

Multiply $- \frac{1}{2} \cdot \frac{3}{8}$ .

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Step 4.9.1

Multiply $\frac{3}{8}$ by $\frac{1}{2}$ .

$- \frac{3}{8 \cdot 2}$

Step 4.9.2

Multiply $8$ by $2$ .

$- \frac{3}{16}$

Step 5

The result can be shown in multiple forms.

Exact Form:

$- \frac{3}{16}$

Decimal Form:

$- 0.1875$