Chapter 5: Problem 50
Find the limits in Problems 1-60; not all limits require use of l'Hôpital's rule. $$ \lim _{x \rightarrow \infty}(1+x)^{1 / x} $$
Short Answer
Expert verified
The limit of \((1+x)^{1/x}\) as \(x\) approaches infinity is 1.
Step by step solution
01
Understanding the Limit Expression
We need to find the limit of the expression \((1+x)^{1/x}\) as \(x\) approaches infinity. The base \((1+x)\) grows indefinitely while the exponent \(\frac{1}{x}\) tends towards zero.
02
Recalling a Relevant Limit Result
Recall that for large values of \(x\), \((1+x)^{1/x}\) can be reinterpreted using the limit definition: \(\lim_{x \to \infty} (1+\frac{1}{x})^x = e\). This can be transformed into our expression.
03
Transforming the Original Expression
Rewrite \((1+x)^{1/x}\) as \((1+\frac{1}{x})^x\), since dividing \(x\) inside \((1+x)\) is equivalent to the division of the base expression by \(x\).
04
Applying Known Limit Results
Using the earlier mentioned result, as \(x\) approaches infinity, \((1+\frac{1}{x})^x\) approaches \(e\). Therefore, our limit \((1+x)^{1/x}\) should tend towards \(1\), not \(e\), as \(x\) goes to infinity.
05
Final Conclusion
After analysis, the correct interpretation of \((1+x)^{1/x}\) as \(x\rightarrow \infty\) reflects the constants more correctly as tending to \(1\) than supporting a limit evaluation of \(e\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Understanding l'Hôpital's Rule
l'Hôpital's Rule is a handy and powerful tool for evaluating certain types of limits. Typically, it is used when direct substitution in a limit leads to an indeterminate form like \( \frac{0}{0} \) or \( \frac{\infty}{\infty} \). In such cases, l'Hôpital's Rule states that:
\[ \lim_{x \to a} \frac{f(x)}{g(x)} = \lim_{x \to a} \frac{f'(x)}{g'(x)} \]
\[ \lim_{x \to a} \frac{f(x)}{g(x)} = \lim_{x \to a} \frac{f'(x)}{g'(x)} \]
- This holds true provided the limit on the right-hand side exists or is infinite.
- "a" can be any real number, infinity, or negative infinity.
Navigating Infinity Limits
When dealing with limits approaching infinity, the behavior of the function can sometimes be unpredictable or counter-intuitive. Instead, it's crucial to understand how different expressions "behave" as variables approach infinity. Oftentimes:
- Polynomial expressions and terms typically grow larger faster than exponential bases with diminishing exponents.
- Expressions approaching forms like \( \left( 1 + \frac{1}{x} \right)^x \) can lead us to constants like "e" when transformations are properly done.
Decoding Exponential Expressions
Exponential expressions, such as \((1+x)^{1/x}\), reveal fascinating behaviors when their terms both grow and shrink. The exponential base here, \(1+x\), heads off to infinity while the exponent \(1/x\) diminishes toward zero. Such expressions are typical in limit problems where understanding base-exponent interactions is crucial.
In some cases:
In some cases:
- Even though the base tends to infinity, a diminishing exponent can converge the entire expression to a particular value.
- This is vividly illustrated with the transformation to \((1+\frac{1}{x})^x\), leading to a result anchored at "e", recognizing the essential behavior often seen with such structures.