Math Problem Statement

Use the properties of limits to find the given limit: lim (x→∞) (2x^5 + 9x^4 - 4x^3) / (26 - 8x^5)

Solution

Let's solve the given limit:

limx2x5+9x44x3268x5\lim_{{x \to \infty}} \frac{2x^5 + 9x^4 - 4x^3}{26 - 8x^5}

Step 1: Factor out the highest power of xx in the numerator and the denominator.

The highest power of xx in both the numerator and denominator is x5x^5. Factor x5x^5 out:

limxx5(2+9x4x2)x5(26x58)\lim_{{x \to \infty}} \frac{x^5\left(2 + \frac{9}{x} - \frac{4}{x^2}\right)}{x^5\left(\frac{26}{x^5} - 8\right)}

Step 2: Simplify the expression.

Since x5x^5 is common in both the numerator and the denominator, it cancels out:

limx2+9x4x226x58\lim_{{x \to \infty}} \frac{2 + \frac{9}{x} - \frac{4}{x^2}}{\frac{26}{x^5} - 8}

Step 3: Apply the limit.

As xx \to \infty, the terms with 9x\frac{9}{x}, 4x2\frac{4}{x^2}, and 26x5\frac{26}{x^5} approach zero:

limx2+0008=28=14\lim_{{x \to \infty}} \frac{2 + 0 - 0}{0 - 8} = \frac{2}{-8} = -\frac{1}{4}

Final Answer:

limx2x5+9x44x3268x5=14\lim_{{x \to \infty}} \frac{2x^5 + 9x^4 - 4x^3}{26 - 8x^5} = -\frac{1}{4}

Would you like more details or have any questions?

Here are five related questions you might find interesting:

  1. How does the degree of the polynomial in the numerator and denominator affect the limit as xx approaches infinity?
  2. What happens if the highest power of xx in the denominator is higher than in the numerator?
  3. Can limits involving infinity always be evaluated by factoring out the highest power of xx?
  4. How would the solution change if the sign of the highest power of xx in the denominator were positive?
  5. How can L'Hôpital's Rule be applied to similar limit problems?

Tip: When dealing with limits approaching infinity, always factor out the highest power of xx to simplify the expression and make the limit easier to evaluate.

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Math Problem Analysis

Mathematical Concepts

Calculus
Limits
Polynomials

Formulas

Limit properties
Factoring polynomials

Theorems

Limits at infinity

Suitable Grade Level

Grades 11-12