Math Problem Statement

Find the limit: lim(x -> ∞) (x^2 + 3x) / sqrt(2x^4 + 3 - 4x)

Solution

The image you provided is a mathematical problem involving limits. The problem asks to find the limit:

limxx2+3x2x4+34x\lim_{x \to \infty} \frac{x^2 + 3x}{\sqrt{2x^4 + 3 - 4x}}

The solution proceeds step by step. Here's a breakdown:

Step 1: Expressing the equation

We are given the limit expression: x2+3x2x4+34x\frac{x^2 + 3x}{\sqrt{2x^4 + 3 - 4x}} The goal is to simplify this expression for xx \to \infty.

Step 2: Factoring out dominant terms

  • In the numerator x2+3xx^2 + 3x, the term x2x^2 dominates as xx \to \infty.
  • In the denominator, the dominant term inside the square root is 2x42x^4 because as xx grows large, other terms become negligible.

We factor out x2x^2 from both the numerator and denominator to make the expression easier to evaluate as xx \to \infty:

\frac{x^2 + 3x}{\sqrt{2x^4 + 3 - 4x}} = \frac{x^2(1 + \frac{3}{x})}{x^2\sqrt{2 + \frac{3}{x^4} - \frac{4}{x^3}}}}

Step 3: Simplification

As xx \to \infty, terms involving 1x,1x3,\frac{1}{x}, \frac{1}{x^3}, and 1x4\frac{1}{x^4} tend to zero. Therefore, the expression simplifies to:

12\frac{1}{\sqrt{2}}

Step 4: Conclusion

Thus, the limit is:

limxx2+3x2x4+34x=12\lim_{x \to \infty} \frac{x^2 + 3x}{\sqrt{2x^4 + 3 - 4x}} = \frac{1}{\sqrt{2}}

Would you like more details on any specific step or the rules applied here?

Further Questions:

  1. Why do we focus on the dominant terms as xx \to \infty?
  2. What happens to smaller order terms as xx approaches infinity?
  3. How does the square root affect the terms in the denominator?
  4. Could this limit be evaluated using L'Hopital's rule instead?
  5. What does the result 12\frac{1}{\sqrt{2}} imply about the growth rates of the numerator and denominator?

Tip:

When evaluating limits as xx \to \infty, always identify and simplify dominant terms, as smaller ones become negligible!

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Math Problem Analysis

Mathematical Concepts

Calculus
Limits
Asymptotic Behavior

Formulas

lim(x -> ∞) f(x) / g(x)
sqrt(a^2 + b) as x -> ∞

Theorems

Limit of a function
Asymptotic Dominance

Suitable Grade Level

Grades 11-12 or College Calculus I