Limit of Rational Function as x Approaches Infinity: (3x^2 + 2x) / (x^2 + 1)

Published on August 31, 2025

Calculus

Find the limit of the rational function (3x^2 + 2x) / (x^2 + 1) as x approaches infinity by dividing by the highest power of x in the denominator or by comparing leading coefficients.

Question

Find the limit: lim(x→∞) (3x² + 2x) / (x² + 1)

Answer

This is a math problem asking to find the limit of a rational function as x approaches infinity.
We need to find the limit:
To evaluate this limit, we can divide both the numerator and the denominator by the highest power of x in the denominator, which is .
Step 1: Divide the numerator by :
Step 2: Divide the denominator by :
Step 3: Rewrite the expression with the divided terms:
Step 4: Apply the limit as to each term. We know that as , for any constant and positive integer .
So, and .
Step 5: Substitute these limits back into the expression:
Alternatively, for rational functions where the degree of the numerator is equal to the degree of the denominator, the limit as (or ) is the ratio of the leading coefficients.
In this problem, the numerator is and its leading coefficient is 3.
The denominator is and its leading coefficient is 1.
Since the degree of the numerator (2) is equal to the degree of the denominator (2), the limit is the ratio of the leading coefficients.
The final answer is .