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Ch. 7 - Transcendental Functions
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Non è quello che usi tu?Cambia libro di testo
Capitolo 7, Problema 7.8.6g

6. Which of the following functions grow faster than ln(x) as x→∞? Which grow at the same rate as ln(x)? Which grow slower?
g. ln(ln x)

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1
Recall that when comparing growth rates of functions as \(x \to \infty\), we often use limits of their ratios to determine which grows faster, slower, or at the same rate.
Identify the two functions to compare: \(f(x) = \ln(x)\) and \(g(x) = \ln(\ln x)\), where \(x\) is large enough so that \(\ln x > 0\).
Consider the limit \(\lim_{x \to \infty} \frac{g(x)}{f(x)} = \lim_{x \to \infty} \frac{\ln(\ln x)}{\ln x}\). This limit will help us understand their relative growth rates.
Analyze the behavior of the limit: since \(\ln x\) grows without bound but more slowly than any power of \(x\), and \(\ln(\ln x)\) grows even more slowly, the numerator grows much slower than the denominator.
Conclude that because the limit tends to zero, \(g(x) = \ln(\ln x)\) grows slower than \(f(x) = \ln x\) as \(x \to \infty\).

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