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Ch. 2 - Limits
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243Non è quello che usi tu?Cambia libro di testo
Capitolo 2, Problema 2.R.49

Determine the following limits.
lim x→∞ (5 + (cos4 x) / (x2 + x + 1))

Guida verificata passo dopo passo
1
Identify the dominant term in the expression as \(x\) approaches infinity. The term \(5\) is constant, and the fraction \(\frac{\cos^4 x}{x^2 + x + 1}\) will determine the behavior of the limit.
Recognize that \(\cos^4 x\) is bounded between 0 and 1, since \(\cos x\) is bounded between -1 and 1.
Consider the denominator \(x^2 + x + 1\), which grows without bound as \(x\) approaches infinity.
Since the numerator \(\cos^4 x\) is bounded and the denominator \(x^2 + x + 1\) grows indefinitely, the fraction \(\frac{\cos^4 x}{x^2 + x + 1}\) approaches 0 as \(x\) approaches infinity.
Conclude that the limit is determined by the constant term, so \(\lim_{x \to \infty} \left(5 + \frac{\cos^4 x}{x^2 + x + 1}\right) = 5\).

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