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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 7.5.55

Indeterminate Powers and Products
Find the limits in Exercises 53–68.
55. lim (x → ∞) (ln x)^(1/x)

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Identify the limit expression: \(\lim_{x \to \infty} (\ln x)^{\frac{1}{x}}\).
Recognize that the expression is of the form \(f(x)^{g(x)}\) where both the base and the exponent depend on \(x\). To handle limits of this form, it is often helpful to rewrite the expression using the exponential and logarithm functions.
Rewrite the expression as \(e^{\ln\left((\ln x)^{\frac{1}{x}}\right)} = e^{\frac{1}{x} \ln(\ln x)}\).
Focus on finding the limit of the exponent: \(\lim_{x \to \infty} \frac{\ln(\ln x)}{x}\). Analyze the behavior of the numerator and denominator as \(x\) approaches infinity.
Since \(\ln(\ln x)\) grows very slowly compared to \(x\), the fraction \(\frac{\ln(\ln x)}{x}\) approaches zero. Therefore, the original limit becomes \(e^0\), which you can interpret to find the final limit.

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