Calculus Examples

$\frac{lim_{x \to 8} x - \sqrt{x^{2} + 9 x + 2}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 1

Split the limit using the Sum of Limits Rule on the limit as $x$ approaches $8$ .

$\frac{lim_{x \to 8} x - lim_{x \to 8} \sqrt{x^{2} + 9 x + 2}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 2

Move the limit under the radical sign.

$\frac{lim_{x \to 8} x - \sqrt{lim_{x \to 8} x^{2} + 9 x + 2}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 3

Split the limit using the Sum of Limits Rule on the limit as $x$ approaches $8$ .

$\frac{lim_{x \to 8} x - \sqrt{lim_{x \to 8} x^{2} + lim_{x \to 8} 9 x + lim_{x \to 8} 2}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 4

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

$\frac{lim_{x \to 8} x - \sqrt{{(lim_{x \to 8} x)}^{2} + lim_{x \to 8} 9 x + lim_{x \to 8} 2}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 5

Move the term $9$ outside of the limit because it is constant with respect to $x$ .

$\frac{lim_{x \to 8} x - \sqrt{{(lim_{x \to 8} x)}^{2} + 9 lim_{x \to 8} x + lim_{x \to 8} 2}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 6

Evaluate the limit of $2$ which is constant as $x$ approaches $8$ .

$\frac{lim_{x \to 8} x - \sqrt{{(lim_{x \to 8} x)}^{2} + 9 lim_{x \to 8} x + 2}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 7

Evaluate the limits by plugging in $8$ for all occurrences of $x$ .

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Step 7.1

Evaluate the limit of $x$ by plugging in $8$ for $x$ .

$\frac{8 - \sqrt{{(lim_{x \to 8} x)}^{2} + 9 lim_{x \to 8} x + 2}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 7.2

Evaluate the limit of $x$ by plugging in $8$ for $x$ .

$\frac{8 - \sqrt{8^{2} + 9 lim_{x \to 8} x + 2}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 7.3

Evaluate the limit of $x$ by plugging in $8$ for $x$ .

$\frac{8 - \sqrt{8^{2} + 9 \cdot 8 + 2}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 8

Simplify the answer.

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Step 8.1

Simplify the numerator.

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Step 8.1.1

Raise $8$ to the power of $2$ .

$\frac{8 - \sqrt{64 + 9 \cdot 8 + 2}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 8.1.2

Multiply $9$ by $8$ .

$\frac{8 - \sqrt{64 + 72 + 2}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 8.1.3

Add $64$ and $72$ .

$\frac{8 - \sqrt{136 + 2}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 8.1.4

Add $136$ and $2$ .

$\frac{8 - \sqrt{138}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 8.2

Multiply $\frac{8 - \sqrt{138}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$ by $\frac{x^{2} + \sqrt{x^{4} + 3 x^{2} + 5}}{x^{2} + \sqrt{x^{4} + 3 x^{2} + 5}}$ .

$\frac{8 - \sqrt{138}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}} \cdot \frac{x^{2} + \sqrt{x^{4} + 3 x^{2} + 5}}{x^{2} + \sqrt{x^{4} + 3 x^{2} + 5}}$

Step 8.3

Multiply $\frac{8 - \sqrt{138}}{x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}}$ by $\frac{x^{2} + \sqrt{x^{4} + 3 x^{2} + 5}}{x^{2} + \sqrt{x^{4} + 3 x^{2} + 5}}$ .

$\frac{(8 - \sqrt{138}) (x^{2} + \sqrt{x^{4} + 3 x^{2} + 5})}{(x^{2} - \sqrt{x^{4} + 3 x^{2} + 5}) (x^{2} + \sqrt{x^{4} + 3 x^{2} + 5})}$

Step 8.4

Expand the denominator using the FOIL method.

$\frac{(8 - \sqrt{138}) (x^{2} + \sqrt{x^{4} + 3 x^{2} + 5})}{x^{4} + x^{2} \sqrt{x^{4} + 3 x^{2} + 5} - \sqrt{x^{4} + 3 x^{2} + 5} x^{2} - {\sqrt{x^{4} + 3 x^{2} + 5}}^{2}}$

Step 8.5

Simplify.

$\frac{(8 - \sqrt{138}) (x^{2} + \sqrt{x^{4} + 3 x^{2} + 5})}{- 3 x^{2} - 5}$

Step 8.6

Expand $(8 - \sqrt{138}) (x^{2} + \sqrt{x^{4} + 3 x^{2} + 5})$ using the FOIL Method.

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Step 8.6.1

Apply the distributive property.

$\frac{8 (x^{2} + \sqrt{x^{4} + 3 x^{2} + 5}) - \sqrt{138} (x^{2} + \sqrt{x^{4} + 3 x^{2} + 5})}{- 3 x^{2} - 5}$

Step 8.6.2

Apply the distributive property.

$\frac{8 x^{2} + 8 \sqrt{x^{4} + 3 x^{2} + 5} - \sqrt{138} (x^{2} + \sqrt{x^{4} + 3 x^{2} + 5})}{- 3 x^{2} - 5}$

Step 8.6.3

Apply the distributive property.

$\frac{8 x^{2} + 8 \sqrt{x^{4} + 3 x^{2} + 5} - \sqrt{138} x^{2} - \sqrt{138} \sqrt{x^{4} + 3 x^{2} + 5}}{- 3 x^{2} - 5}$

Step 8.7

Combine using the product rule for radicals.

$\frac{8 x^{2} + 8 \sqrt{x^{4} + 3 x^{2} + 5} - \sqrt{138} x^{2} - \sqrt{(x^{4} + 3 x^{2} + 5) \cdot 138}}{- 3 x^{2} - 5}$

Step 8.8

Reorder factors in $8 x^{2} + 8 \sqrt{x^{4} + 3 x^{2} + 5} - \sqrt{138} x^{2} - \sqrt{(x^{4} + 3 x^{2} + 5) \cdot 138}$ .

$\frac{8 x^{2} + 8 \sqrt{x^{4} + 3 x^{2} + 5} - \sqrt{138} x^{2} - \sqrt{138 (x^{4} + 3 x^{2} + 5)}}{- 3 x^{2} - 5}$

Step 8.9

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

$\frac{8 x^{2} + 8 \sqrt{x^{4} + 3 x^{2} + 5} - \sqrt{138} x^{2} - \sqrt{138 (x^{4} + 3 x^{2} + 5)}}{- (3 x^{2}) - 5}$

Step 8.10

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

$\frac{8 x^{2} + 8 \sqrt{x^{4} + 3 x^{2} + 5} - \sqrt{138} x^{2} - \sqrt{138 (x^{4} + 3 x^{2} + 5)}}{- (3 x^{2}) - 1 (5)}$

Step 8.11

Factor $- 1$ out of $- (3 x^{2}) - 1 (5)$ .

$\frac{8 x^{2} + 8 \sqrt{x^{4} + 3 x^{2} + 5} - \sqrt{138} x^{2} - \sqrt{138 (x^{4} + 3 x^{2} + 5)}}{- (3 x^{2} + 5)}$

Step 8.12

Rewrite $- (3 x^{2} + 5)$ as $- 1 (3 x^{2} + 5)$ .

$\frac{8 x^{2} + 8 \sqrt{x^{4} + 3 x^{2} + 5} - \sqrt{138} x^{2} - \sqrt{138 (x^{4} + 3 x^{2} + 5)}}{- 1 (3 x^{2} + 5)}$

Step 8.13

Move the negative in front of the fraction.

$- \frac{8 x^{2} + 8 \sqrt{x^{4} + 3 x^{2} + 5} - \sqrt{138} x^{2} - \sqrt{138 (x^{4} + 3 x^{2} + 5)}}{3 x^{2} + 5}$