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Ch. 2 - Limits and Continuity
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Non è quello che usi tu?Cambia libro di testo
Capitolo 2, Problema 2.6.15

Limits of Rational Functions


In Exercises 13–22, find the limit of each rational function (a) as x → ∞ and (b) as x → −∞. Write ∞ or −∞ where appropriate.


f(x) = (x + 1)/(x² + 3)

Guida verificata passo dopo passo
1
Step 1: To find the limit of the rational function \( f(x) = \frac{x + 1}{x^2 + 3} \) as \( x \to \infty \), start by analyzing the degrees of the numerator and the denominator. The numerator \( x + 1 \) is of degree 1, and the denominator \( x^2 + 3 \) is of degree 2.
Step 2: Since the degree of the denominator is greater than the degree of the numerator, the limit as \( x \to \infty \) will be determined by the leading terms. Divide each term in the numerator and the denominator by \( x^2 \), the highest power of \( x \) in the denominator.
Step 3: After dividing, the expression becomes \( \frac{\frac{x}{x^2} + \frac{1}{x^2}}{\frac{x^2}{x^2} + \frac{3}{x^2}} = \frac{\frac{1}{x} + \frac{1}{x^2}}{1 + \frac{3}{x^2}} \). As \( x \to \infty \), both \( \frac{1}{x} \) and \( \frac{1}{x^2} \) approach 0.
Step 4: Therefore, the limit of the function as \( x \to \infty \) is \( \frac{0 + 0}{1 + 0} = 0 \).
Step 5: To find the limit as \( x \to -\infty \), repeat the same process. The behavior of the function is similar because the terms \( \frac{1}{x} \) and \( \frac{1}{x^2} \) also approach 0 as \( x \to -\infty \). Thus, the limit is \( \frac{0 + 0}{1 + 0} = 0 \).

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