Math Problem Statement

Question content area top Part 1 Determine the following limit. ModifyingBelow lim With x right arrow infinityStartFraction 36 x cubed plus 2 x squared minus 4 x Over 30 x cubed plus x squared plus 3 x plus 3 EndFraction

Solution

We are asked to determine the following limit:

limx36x3+2x24x30x3+x2+3x+3\lim_{x \to \infty} \frac{36x^3 + 2x^2 - 4x}{30x^3 + x^2 + 3x + 3}

Step-by-step solution:

  1. Identify the highest degree terms:
    Both the numerator and the denominator contain terms of different powers of xx, but as xx \to \infty, the highest degree terms (those involving x3x^3) will dominate.

    • In the numerator, the highest degree term is 36x336x^3.
    • In the denominator, the highest degree term is 30x330x^3.
  2. Simplify the expression:
    We can factor out x3x^3 from both the numerator and denominator:

    36x3+2x24x30x3+x2+3x+3=x3(36+2x4x2)x3(30+1x+3x2+3x3)\frac{36x^3 + 2x^2 - 4x}{30x^3 + x^2 + 3x + 3} = \frac{x^3(36 + \frac{2}{x} - \frac{4}{x^2})}{x^3(30 + \frac{1}{x} + \frac{3}{x^2} + \frac{3}{x^3})}

  3. Cancel the common factor of x3x^3: =36+2x4x230+1x+3x2+3x3= \frac{36 + \frac{2}{x} - \frac{4}{x^2}}{30 + \frac{1}{x} + \frac{3}{x^2} + \frac{3}{x^3}}

  4. Take the limit as xx \to \infty: As xx approaches infinity, all terms involving fractions with xx in the denominator (like 2x\frac{2}{x}, 4x2\frac{4}{x^2}, etc.) approach zero.

    Thus, we get: limx36+2x4x230+1x+3x2+3x3=3630=65\lim_{x \to \infty} \frac{36 + \frac{2}{x} - \frac{4}{x^2}}{30 + \frac{1}{x} + \frac{3}{x^2} + \frac{3}{x^3}} = \frac{36}{30} = \frac{6}{5}

Final Answer:

limx36x3+2x24x30x3+x2+3x+3=65\lim_{x \to \infty} \frac{36x^3 + 2x^2 - 4x}{30x^3 + x^2 + 3x + 3} = \frac{6}{5}

Would you like any further explanation or have additional questions about this problem?

Further exploration:

  1. How does the behavior of the function change as xx \to -\infty?
  2. What would the limit be if the highest degree term in the numerator and denominator had different powers (e.g., if it was x2x^2)?
  3. How do you approach limits involving rational functions when the degrees of the terms in the numerator and denominator are equal?
  4. What would happen if the terms involving x3x^3 had opposite signs?
  5. How can this limit help us understand asymptotic behavior in other rational functions?

Tip: When working with limits of rational functions, focus on the highest degree terms in both the numerator and denominator, as they will dominate the behavior of the function as xx \to \infty.

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Math Problem Analysis

Mathematical Concepts

Limits
Rational Functions
Asymptotic Behavior
Polynomial Functions

Formulas

Limit of Rational Functions as x approaches infinity
Simplification of Rational Expressions

Theorems

Dominant Term Theorem (highest degree term dominates as x approaches infinity)

Suitable Grade Level

Grades 11-12