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Ch. 4 - Applications of the Derivative
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243Non è quello che usi tu?Cambia libro di testo
Capitolo 4, Problema 4.R.79

60–81. Limits Evaluate the following limits. Use l’Hôpital’s Rule when needed. 
lim_x→∞ (1 - (3/x))ˣ

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Recognize that the limit \( \lim_{x \to \infty} \left(1 - \frac{3}{x}\right)^x \) is of the indeterminate form \(1^\infty\). This suggests the use of the exponential limit property.
Rewrite the expression using the natural exponential function: \( \lim_{x \to \infty} \left(1 - \frac{3}{x}\right)^x = \lim_{x \to \infty} e^{x \ln\left(1 - \frac{3}{x}\right)} \).
Focus on evaluating the exponent \( \lim_{x \to \infty} x \ln\left(1 - \frac{3}{x}\right) \). This is still an indeterminate form \(0 \cdot (-\infty)\).
Use the approximation \( \ln(1 + u) \approx u \) for small \(u\), so \( \ln\left(1 - \frac{3}{x}\right) \approx -\frac{3}{x} \). Substitute this into the limit: \( \lim_{x \to \infty} x \left(-\frac{3}{x}\right) = \lim_{x \to \infty} -3 \).
Conclude that the original limit is \( e^{-3} \) by substituting back into the exponential form: \( \lim_{x \to \infty} e^{x \ln\left(1 - \frac{3}{x}\right)} = e^{-3} \).

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Limits

Limits are fundamental concepts in calculus that describe the behavior of a function as its input approaches a certain value. They help in understanding the function's behavior at points where it may not be explicitly defined, such as at infinity or discontinuities. Evaluating limits is crucial for determining the continuity and differentiability of functions.
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