Math Problem Statement

lim┬(n⟶∞)⁡〖(3n^2+4n+7)/(2+3n+4n^2 )〗

Solution

To evaluate the limit:

limn3n2+4n+72+3n+4n2\lim_{n \to \infty} \frac{3n^2 + 4n + 7}{2 + 3n + 4n^2}

Step-by-step solution:

  1. Identify the dominant terms:

    • In the numerator 3n2+4n+73n^2 + 4n + 7, the dominant term as nn approaches infinity is 3n23n^2, since it has the highest degree.
    • In the denominator 2+3n+4n22 + 3n + 4n^2, the dominant term is 4n24n^2.
  2. Simplify the fraction by dividing the numerator and denominator by n2n^2 (the highest power of nn present in the expression):

    3n2+4n+72+3n+4n2=3n2/n2+4n/n2+7/n22/n2+3n/n2+4n2/n2\frac{3n^2 + 4n + 7}{2 + 3n + 4n^2} = \frac{3n^2/n^2 + 4n/n^2 + 7/n^2}{2/n^2 + 3n/n^2 + 4n^2/n^2}

    This simplifies to:

    =3+4n+7n22n2+3n+4= \frac{3 + \frac{4}{n} + \frac{7}{n^2}}{\frac{2}{n^2} + \frac{3}{n} + 4}

  3. Take the limit as nn \to \infty:

    • As nn \to \infty, 4n0\frac{4}{n} \to 0, 7n20\frac{7}{n^2} \to 0, 2n20\frac{2}{n^2} \to 0, and 3n0\frac{3}{n} \to 0.
    • This leaves us with:

    limn3+0+00+0+4=34\lim_{n \to \infty} \frac{3 + 0 + 0}{0 + 0 + 4} = \frac{3}{4}

Final answer:

limn3n2+4n+72+3n+4n2=34\lim_{n \to \infty} \frac{3n^2 + 4n + 7}{2 + 3n + 4n^2} = \frac{3}{4}

Would you like further explanation on any step, or have any questions about similar limits?


Here are 5 related questions:

  1. How do you evaluate limits of rational functions involving higher powers of nn?
  2. What is the limit of the expression n2+2nn2+3\frac{n^2 + 2n}{n^2 + 3} as nn \to \infty?
  3. How do you approach limits involving exponential and polynomial terms?
  4. What happens if the degrees of the numerator and denominator are equal in a rational function?
  5. Can you explain the intuition behind dividing both the numerator and denominator by the highest power of nn?

Tip: When evaluating limits for rational functions, always identify the terms with the highest powers of nn, and divide through by those terms to simplify the limit evaluation.

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Math Problem Analysis

Mathematical Concepts

Limits
Rational Functions
Asymptotic Behavior
Polynomials

Formulas

lim_{n -> ∞} (a_n / b_n) = lim_{n -> ∞} (a_n / b_n) for dominant terms

Theorems

Dominant term analysis for limits
Limit laws for rational functions

Suitable Grade Level

Grades 11-12