Math Problem Statement

Evaluate the limit: lim (x → ∞) (3x^3 - x√(x+1) - 2) / (0.2x - 4x^3 - 3).

Solution

The problem you uploaded involves evaluating the following limit as xx \to \infty:

limx3x3xx+120.2x4x33\lim_{x \to \infty} \frac{3x^3 - x\sqrt{x+1} - 2}{0.2x - 4x^3 - 3}

To solve this limit, we will analyze the behavior of both the numerator and the denominator as xx \to \infty.

Step-by-step breakdown:

  1. Numerator:

    • The highest degree term in the numerator is 3x33x^3, which dominates as xx \to \infty.
    • The term involving xx+1x\sqrt{x+1} needs to be simplified. For large xx, x+1x\sqrt{x+1} \approx \sqrt{x}, so xx+1xx=x3/2x\sqrt{x+1} \approx x \cdot \sqrt{x} = x^{3/2}.
    • As a result, the numerator behaves like 3x3x3/223x^3 - x^{3/2} - 2.
  2. Denominator:

    • The highest degree term in the denominator is 4x3-4x^3, which dominates as xx \to \infty.
    • The other terms like 0.2x0.2x and 3-3 are negligible compared to x3x^3 for large xx.

Thus, for large xx, the expression behaves like:

3x34x3\frac{3x^3}{-4x^3}

This simplifies to:

34-\frac{3}{4}

Conclusion:

The limit is:

limx3x3xx+120.2x4x33=34\lim_{x \to \infty} \frac{3x^3 - x\sqrt{x+1} - 2}{0.2x - 4x^3 - 3} = -\frac{3}{4}

Would you like any further details or clarification?

Here are some additional questions that might interest you:

  1. How do you find limits of indeterminate forms?
  2. What happens when the highest degree terms in both the numerator and denominator are the same?
  3. How do you deal with radical terms in limits as xx \to \infty?
  4. Can you apply L'Hopital's Rule to this problem?
  5. How does the behavior of the function change if the limit approaches negative infinity?

Tip: When evaluating limits involving polynomials and radicals as xx \to \infty, always focus on the highest degree terms, as these dominate the behavior of the function.

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Math Problem Analysis

Mathematical Concepts

Limits
Asymptotic Behavior
Polynomial and Radical Functions

Formulas

√(x+1) ≈ √x for large x
Highest degree term dominates in polynomial limits

Theorems

Limit properties
Polynomial dominance theorem

Suitable Grade Level

Grades 11-12, College Calculus