Math Problem Statement

Find the limit of \( \frac{2x^4 + 3x^2}{3x^4 + 5x} \) as \( x \to \infty \).

Solution

This is a limit problem where you need to evaluate the given rational function as xx \to \infty:

limx2x4+3x23x4+5x.\lim_{x \to \infty} \frac{2x^4 + 3x^2}{3x^4 + 5x}.

Step-by-Step Solution:

  1. Identify the highest degree of xx:

    • In the numerator: 2x42x^4 is the highest term.
    • In the denominator: 3x43x^4 is the highest term.
  2. Divide numerator and denominator by x4x^4: To simplify, divide each term by x4x^4, the highest power:

    2x4+3x23x4+5x=2x4x4+3x2x43x4x4+5xx4=2+3x23+5x3.\frac{2x^4 + 3x^2}{3x^4 + 5x} = \frac{\frac{2x^4}{x^4} + \frac{3x^2}{x^4}}{\frac{3x^4}{x^4} + \frac{5x}{x^4}} = \frac{2 + \frac{3}{x^2}}{3 + \frac{5}{x^3}}.

  3. Simplify as xx \to \infty:

    • As xx \to \infty:
      • 3x20\frac{3}{x^2} \to 0,
      • 5x30\frac{5}{x^3} \to 0.

    The expression becomes:

    2+03+0=23.\frac{2 + 0}{3 + 0} = \frac{2}{3}.

Final Answer:

limx2x4+3x23x4+5x=23.\lim_{x \to \infty} \frac{2x^4 + 3x^2}{3x^4 + 5x} = \frac{2}{3}.


Would you like further details or assistance with a similar problem? Here are 5 related questions for practice:

  1. How do you find the limit of 5x3+xx3+7\frac{5x^3 + x}{x^3 + 7} as xx \to \infty?
  2. What happens if the degree of the numerator is higher than the degree of the denominator in a rational function limit?
  3. Can you explain the significance of dominant terms when evaluating limits at infinity?
  4. How does L’Hopital’s Rule apply to limits at infinity?
  5. What happens if both numerator and denominator contain exponential functions?

Tip: Always simplify rational functions by dividing by the highest power of xx to easily identify dominant terms.

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Math Problem Analysis

Mathematical Concepts

Limits at infinity
Rational functions
Simplifying polynomials

Formulas

Divide numerator and denominator by the highest power of x
\( \lim_{x \to \infty} \frac{a}{b} = \frac{a}{b} \) if terms vanish as \( x \to \infty \)

Theorems

Dominance of the highest power of x in rational functions
Behavior of polynomial terms as \( x \to \infty \)

Suitable Grade Level

Grade 11-12 (High School Calculus)