Calculus Examples

$lim_{x \to \infty} \frac{4 x^{3} - 2 x^{2} + 5 x - 7}{x^{2} - 4 x - 2 x^{3} - 1}$

Step 1

Divide the numerator and denominator by the highest power of $x$ in the denominator, which is $x^{3}$ .

$lim_{x \to \infty} \frac{\frac{4 x^{3}}{x^{3}} + \frac{- 2 x^{2}}{x^{3}} + \frac{5 x}{x^{3}} + \frac{- 7}{x^{3}}}{\frac{x^{2}}{x^{3}} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2

Evaluate the limit.

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Step 2.1

Simplify each term.

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Step 2.1.1

Cancel the common factor of $x^{3}$ .

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Step 2.1.1.1

Cancel the common factor.

Step 2.1.1.2

Divide $4$ by $1$ .

$lim_{x \to \infty} \frac{4 + \frac{- 2 x^{2}}{x^{3}} + \frac{5 x}{x^{3}} + \frac{- 7}{x^{3}}}{\frac{x^{2}}{x^{3}} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.1.2

Cancel the common factor of $x^{2}$ and $x^{3}$ .

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Step 2.1.2.1

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

$lim_{x \to \infty} \frac{4 + \frac{x^{2} \cdot - 2}{x^{3}} + \frac{5 x}{x^{3}} + \frac{- 7}{x^{3}}}{\frac{x^{2}}{x^{3}} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.1.2.2

Cancel the common factors.

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Step 2.1.2.2.1

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

$lim_{x \to \infty} \frac{4 + \frac{x^{2} \cdot - 2}{x^{2} x} + \frac{5 x}{x^{3}} + \frac{- 7}{x^{3}}}{\frac{x^{2}}{x^{3}} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.1.2.2.2

Cancel the common factor.

$lim_{x \to \infty} \frac{4 + \frac{x^{2} \cdot - 2}{x^{2} x} + \frac{5 x}{x^{3}} + \frac{- 7}{x^{3}}}{\frac{x^{2}}{x^{3}} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.1.2.2.3

Rewrite the expression.

$lim_{x \to \infty} \frac{4 + \frac{- 2}{x} + \frac{5 x}{x^{3}} + \frac{- 7}{x^{3}}}{\frac{x^{2}}{x^{3}} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.1.3

Move the negative in front of the fraction.

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5 x}{x^{3}} + \frac{- 7}{x^{3}}}{\frac{x^{2}}{x^{3}} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.1.4

Cancel the common factor of $x$ and $x^{3}$ .

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Step 2.1.4.1

Factor $x$ out of $5 x$ .

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{x \cdot 5}{x^{3}} + \frac{- 7}{x^{3}}}{\frac{x^{2}}{x^{3}} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.1.4.2

Cancel the common factors.

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Step 2.1.4.2.1

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

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{x \cdot 5}{x \cdot x^{2}} + \frac{- 7}{x^{3}}}{\frac{x^{2}}{x^{3}} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.1.4.2.2

Cancel the common factor.

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{x \cdot 5}{x \cdot x^{2}} + \frac{- 7}{x^{3}}}{\frac{x^{2}}{x^{3}} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.1.4.2.3

Rewrite the expression.

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5}{x^{2}} + \frac{- 7}{x^{3}}}{\frac{x^{2}}{x^{3}} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.1.5

Move the negative in front of the fraction.

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5}{x^{2}} - \frac{7}{x^{3}}}{\frac{x^{2}}{x^{3}} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.2

Simplify each term.

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Step 2.2.1

Cancel the common factor of $x^{2}$ and $x^{3}$ .

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Step 2.2.1.1

Multiply by $1$ .

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5}{x^{2}} - \frac{7}{x^{3}}}{\frac{x^{2} \cdot 1}{x^{3}} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.2.1.2

Cancel the common factors.

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Step 2.2.1.2.1

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

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5}{x^{2}} - \frac{7}{x^{3}}}{\frac{x^{2} \cdot 1}{x^{2} x} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.2.1.2.2

Cancel the common factor.

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5}{x^{2}} - \frac{7}{x^{3}}}{\frac{x^{2} \cdot 1}{x^{2} x} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.2.1.2.3

Rewrite the expression.

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5}{x^{2}} - \frac{7}{x^{3}}}{\frac{1}{x} + \frac{- 4 x}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.2.2

Cancel the common factor of $x$ and $x^{3}$ .

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Step 2.2.2.1

Factor $x$ out of $- 4 x$ .

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5}{x^{2}} - \frac{7}{x^{3}}}{\frac{1}{x} + \frac{x \cdot - 4}{x^{3}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.2.2.2

Cancel the common factors.

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Step 2.2.2.2.1

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

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5}{x^{2}} - \frac{7}{x^{3}}}{\frac{1}{x} + \frac{x \cdot - 4}{x \cdot x^{2}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.2.2.2.2

Cancel the common factor.

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5}{x^{2}} - \frac{7}{x^{3}}}{\frac{1}{x} + \frac{x \cdot - 4}{x \cdot x^{2}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.2.2.2.3

Rewrite the expression.

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5}{x^{2}} - \frac{7}{x^{3}}}{\frac{1}{x} + \frac{- 4}{x^{2}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.2.3

Move the negative in front of the fraction.

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5}{x^{2}} - \frac{7}{x^{3}}}{\frac{1}{x} - \frac{4}{x^{2}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.2.4

Cancel the common factor of $x^{3}$ .

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Step 2.2.4.1

Cancel the common factor.

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5}{x^{2}} - \frac{7}{x^{3}}}{\frac{1}{x} - \frac{4}{x^{2}} + \frac{- 2 x^{3}}{x^{3}} - \frac{1}{x^{3}}}$

Step 2.2.4.2

Divide $- 2$ by $1$ .

$lim_{x \to \infty} \frac{4 - \frac{2}{x} + \frac{5}{x^{2}} - \frac{7}{x^{3}}}{\frac{1}{x} - \frac{4}{x^{2}} - 2 - \frac{1}{x^{3}}}$

Step 2.3

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

$\frac{lim_{x \to \infty} 4 - \frac{2}{x} + \frac{5}{x^{2}} - \frac{7}{x^{3}}}{lim_{x \to \infty} \frac{1}{x} - \frac{4}{x^{2}} - 2 - \frac{1}{x^{3}}}$

Step 2.4

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

$\frac{lim_{x \to \infty} 4 - lim_{x \to \infty} \frac{2}{x} + lim_{x \to \infty} \frac{5}{x^{2}} - lim_{x \to \infty} \frac{7}{x^{3}}}{lim_{x \to \infty} \frac{1}{x} - \frac{4}{x^{2}} - 2 - \frac{1}{x^{3}}}$

Step 2.5

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

$\frac{4 - lim_{x \to \infty} \frac{2}{x} + lim_{x \to \infty} \frac{5}{x^{2}} - lim_{x \to \infty} \frac{7}{x^{3}}}{lim_{x \to \infty} \frac{1}{x} - \frac{4}{x^{2}} - 2 - \frac{1}{x^{3}}}$

Step 2.6

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

$\frac{4 - 2 lim_{x \to \infty} \frac{1}{x} + lim_{x \to \infty} \frac{5}{x^{2}} - lim_{x \to \infty} \frac{7}{x^{3}}}{lim_{x \to \infty} \frac{1}{x} - \frac{4}{x^{2}} - 2 - \frac{1}{x^{3}}}$

Step 3

Since its numerator approaches a real number while its denominator is unbounded, the fraction $\frac{1}{x}$ approaches $0$ .

$\frac{4 - 2 \cdot 0 + lim_{x \to \infty} \frac{5}{x^{2}} - lim_{x \to \infty} \frac{7}{x^{3}}}{lim_{x \to \infty} \frac{1}{x} - \frac{4}{x^{2}} - 2 - \frac{1}{x^{3}}}$

Step 4

Move the term $5$ outside of the limit because it is constant with respect to $x$ .

$\frac{4 - 2 \cdot 0 + 5 lim_{x \to \infty} \frac{1}{x^{2}} - lim_{x \to \infty} \frac{7}{x^{3}}}{lim_{x \to \infty} \frac{1}{x} - \frac{4}{x^{2}} - 2 - \frac{1}{x^{3}}}$

Step 5

Since its numerator approaches a real number while its denominator is unbounded, the fraction $\frac{1}{x^{2}}$ approaches $0$ .

$\frac{4 - 2 \cdot 0 + 5 \cdot 0 - lim_{x \to \infty} \frac{7}{x^{3}}}{lim_{x \to \infty} \frac{1}{x} - \frac{4}{x^{2}} - 2 - \frac{1}{x^{3}}}$

Step 6

Move the term $7$ outside of the limit because it is constant with respect to $x$ .

$\frac{4 - 2 \cdot 0 + 5 \cdot 0 - 7 lim_{x \to \infty} \frac{1}{x^{3}}}{lim_{x \to \infty} \frac{1}{x} - \frac{4}{x^{2}} - 2 - \frac{1}{x^{3}}}$

Step 7

Since its numerator approaches a real number while its denominator is unbounded, the fraction $\frac{1}{x^{3}}$ approaches $0$ .

$\frac{4 - 2 \cdot 0 + 5 \cdot 0 - 7 \cdot 0}{lim_{x \to \infty} \frac{1}{x} - \frac{4}{x^{2}} - 2 - \frac{1}{x^{3}}}$

Step 8

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

$\frac{4 - 2 \cdot 0 + 5 \cdot 0 - 7 \cdot 0}{lim_{x \to \infty} \frac{1}{x} - lim_{x \to \infty} \frac{4}{x^{2}} - lim_{x \to \infty} 2 - lim_{x \to \infty} \frac{1}{x^{3}}}$

Step 9

Since its numerator approaches a real number while its denominator is unbounded, the fraction $\frac{1}{x}$ approaches $0$ .

$\frac{4 - 2 \cdot 0 + 5 \cdot 0 - 7 \cdot 0}{0 - lim_{x \to \infty} \frac{4}{x^{2}} - lim_{x \to \infty} 2 - lim_{x \to \infty} \frac{1}{x^{3}}}$

Step 10

Move the term $4$ outside of the limit because it is constant with respect to $x$ .

$\frac{4 - 2 \cdot 0 + 5 \cdot 0 - 7 \cdot 0}{0 - 4 lim_{x \to \infty} \frac{1}{x^{2}} - lim_{x \to \infty} 2 - lim_{x \to \infty} \frac{1}{x^{3}}}$

Step 11

Since its numerator approaches a real number while its denominator is unbounded, the fraction $\frac{1}{x^{2}}$ approaches $0$ .

$\frac{4 - 2 \cdot 0 + 5 \cdot 0 - 7 \cdot 0}{0 - 4 \cdot 0 - lim_{x \to \infty} 2 - lim_{x \to \infty} \frac{1}{x^{3}}}$

Step 12

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

$\frac{4 - 2 \cdot 0 + 5 \cdot 0 - 7 \cdot 0}{0 - 4 \cdot 0 - 1 \cdot 2 - lim_{x \to \infty} \frac{1}{x^{3}}}$

Step 13

Since its numerator approaches a real number while its denominator is unbounded, the fraction $\frac{1}{x^{3}}$ approaches $0$ .

$\frac{4 - 2 \cdot 0 + 5 \cdot 0 - 7 \cdot 0}{0 - 4 \cdot 0 - 1 \cdot 2 - 0}$

Step 14

Simplify the answer.

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Step 14.1

Simplify the numerator.

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Step 14.1.1

Multiply $- 2$ by $0$ .

$\frac{4 + 0 + 5 \cdot 0 - 7 \cdot 0}{0 - 4 \cdot 0 - 1 \cdot 2 - 0}$

Step 14.1.2

Multiply $5$ by $0$ .

$\frac{4 + 0 + 0 - 7 \cdot 0}{0 - 4 \cdot 0 - 1 \cdot 2 - 0}$

Step 14.1.3

Multiply $- 7$ by $0$ .

$\frac{4 + 0 + 0 + 0}{0 - 4 \cdot 0 - 1 \cdot 2 - 0}$

Step 14.1.4

Add $4 + 0 + 0$ and $0$ .

$\frac{4 + 0 + 0}{0 - 4 \cdot 0 - 1 \cdot 2 - 0}$

Step 14.1.5

Add $4 + 0$ and $0$ .

$\frac{4 + 0}{0 - 4 \cdot 0 - 1 \cdot 2 - 0}$

Step 14.1.6

Add $4$ and $0$ .

$\frac{4}{0 - 4 \cdot 0 - 1 \cdot 2 - 0}$

Step 14.2

Simplify the denominator.

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Step 14.2.1

Multiply $- 4$ by $0$ .

$\frac{4}{0 + 0 - 1 \cdot 2 - 0}$

Step 14.2.2

Multiply $- 1$ by $2$ .

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

Step 14.2.3

Multiply $- 1$ by $0$ .

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

Step 14.2.4

Add $0 + 0 - 2$ and $0$ .

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

Step 14.2.5

Add $0$ and $0$ .

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

Step 14.2.6

Subtract $2$ from $0$ .

$\frac{4}{- 2}$

Step 14.3

Divide $4$ by $- 2$ .

$- 2$