Math Problem Statement

Evaluate the limit \( \lim_{{x \to \infty}} \frac{9x^3 - 1}{3x^3 + 10} \)

Solution

The limit problem given is:

limx9x313x3+10\lim_{{x \to \infty}} \frac{9x^3 - 1}{3x^3 + 10}

To solve this, we’ll analyze the behavior of the function as xx approaches infinity by dividing both the numerator and the denominator by the highest power of xx in the denominator, which is x3x^3.

Step-by-Step Solution:

  1. Rewrite the expression by dividing each term by x3x^3: 9x313x3+10=9x3x31x33x3x3+10x3\frac{9x^3 - 1}{3x^3 + 10} = \frac{\frac{9x^3}{x^3} - \frac{1}{x^3}}{\frac{3x^3}{x^3} + \frac{10}{x^3}}

  2. Simplify each term: =91x33+10x3= \frac{9 - \frac{1}{x^3}}{3 + \frac{10}{x^3}}

  3. As xx \to \infty, the terms 1x3\frac{1}{x^3} and 10x3\frac{10}{x^3} approach zero: =903+0=93=3= \frac{9 - 0}{3 + 0} = \frac{9}{3} = 3

Conclusion:

limx9x313x3+10=3\lim_{{x \to \infty}} \frac{9x^3 - 1}{3x^3 + 10} = 3

Would you like further explanation on any steps, or do you have more questions?

Here are five related questions that can deepen your understanding:

  1. How would the limit change if the highest power in the denominator was different from the numerator?
  2. What if the coefficient of x3x^3 in the denominator was zero?
  3. How do limits behave when dealing with polynomials of different degrees?
  4. What are some other methods for evaluating limits at infinity?
  5. How would this problem change if xx \to -\infty instead?

Tip: When evaluating limits at infinity for rational functions, compare the degrees of the polynomials in the numerator and denominator to determine the behavior.

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Math Problem Analysis

Mathematical Concepts

Limits
Polynomial Functions
Asymptotic Behavior

Formulas

Limit of a rational function at infinity \( \lim_{{x \to \infty}} \frac{a_n x^n + ...}{b_n x^n + ...} = \frac{a_n}{b_n} \) when the degrees are equal

Theorems

Limit at Infinity for Rational Functions

Suitable Grade Level

College Calculus