Math Problem Statement

evaluate the limit limxe1x11x\lim_{x\rarr\infty}\frac{e^{\frac{1}{x}}-1}{\frac{1}{x}}

Solution

To evaluate the limit

limxe1x11x,\lim_{x \to \infty} \frac{e^{\frac{1}{x}} - 1}{\frac{1}{x}},

we can start by rewriting it in a more convenient form to apply L'Hôpital's Rule.

Step 1: Rewrite the limit

As xx \to \infty, 1x0\frac{1}{x} \to 0. Thus, we can rewrite the limit in terms of a new variable u=1xu = \frac{1}{x}. Then as xx \to \infty, u0+u \to 0^+. Substituting u=1xu = \frac{1}{x} into the limit, we get:

limxe1x11x=limu0+eu1u.\lim_{x \to \infty} \frac{e^{\frac{1}{x}} - 1}{\frac{1}{x}} = \lim_{u \to 0^+} \frac{e^u - 1}{u}.

Step 2: Apply L'Hôpital's Rule

The limit now has the form 00\frac{0}{0} as u0u \to 0, so we can apply L'Hôpital's Rule by differentiating the numerator and denominator with respect to uu:

limu0eu1u=limu0eu1.\lim_{u \to 0} \frac{e^u - 1}{u} = \lim_{u \to 0} \frac{e^u}{1}.

Step 3: Evaluate the limit

Now, substituting u=0u = 0 into the remaining expression:

limu0eu=e0=1.\lim_{u \to 0} e^u = e^0 = 1.

Final Answer

Therefore, the limit is

limxe1x11x=1.\lim_{x \to \infty} \frac{e^{\frac{1}{x}} - 1}{\frac{1}{x}} = 1.

Would you like further details on this solution?

Here are 5 related questions you might find helpful:

  1. How would you evaluate limx0e2x1x\lim_{x \to 0} \frac{e^{2x} - 1}{x}?
  2. What is limxe2x11x\lim_{x \to \infty} \frac{e^{\frac{2}{x}} - 1}{\frac{1}{x}}?
  3. How do you solve limx0ln(1+x)x\lim_{x \to 0} \frac{\ln(1 + x)}{x}?
  4. How would you approach limx0sinxx\lim_{x \to 0} \frac{\sin x}{x} using similar techniques?
  5. How does the expansion of eue^u help in finding limits like this?

Tip: Using substitutions like u=1xu = \frac{1}{x} can simplify limits, making it easier to apply L'Hôpital's Rule.

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Math Problem Analysis

Mathematical Concepts

Limits
L'Hôpital's Rule
Exponential Functions
Variable Substitution

Formulas

L'Hôpital's Rule: \( \lim_{x \to a} \frac{f(x)}{g(x)} = \lim_{x \to a} \frac{f'(x)}{g'(x)} \) when \( \frac{f(x)}{g(x)} \) is indeterminate

Theorems

L'Hôpital's Rule

Suitable Grade Level

Grades 11-12, College Calculus