Math Problem Statement

For the limit below, find values of Ξ΄ that correspond to the Ξ΅ values. lim_(x->0) (e^x - 1)/x = 1 πœ€ 𝛿 0.5

Incorrect: Your answer is incorrect. (Round your answer to three decimal places.)

Solution

We are given the limit:

lim⁑xβ†’0exβˆ’1x=1\lim_{{x \to 0}} \frac{e^x - 1}{x} = 1

The goal is to find values of Ξ΄\delta that correspond to a given Ο΅\epsilon.

Definition of Limit:

For the limit lim⁑xβ†’0f(x)=L\lim_{{x \to 0}} f(x) = L, we say that the limit equals LL if, for every Ο΅>0\epsilon > 0, there exists a Ξ΄>0\delta > 0 such that whenever 0<∣xβˆ’0∣<Ξ΄0 < |x - 0| < \delta, the following holds:

∣f(x)βˆ’L∣<Ο΅|f(x) - L| < \epsilon

In this case, f(x)=exβˆ’1xf(x) = \frac{e^x - 1}{x} and L=1L = 1.

We need to satisfy:

∣exβˆ’1xβˆ’1∣<Ο΅\left| \frac{e^x - 1}{x} - 1 \right| < \epsilon

Simplifying the Expression:

∣exβˆ’1xβˆ’1∣=∣exβˆ’1βˆ’xx∣\left| \frac{e^x - 1}{x} - 1 \right| = \left| \frac{e^x - 1 - x}{x} \right| So we need:

∣exβˆ’1βˆ’xx∣<Ο΅\left| \frac{e^x - 1 - x}{x} \right| < \epsilon

Now, we must find Ξ΄\delta in terms of Ο΅\epsilon.

Step-by-Step Solution:

  1. We need to solve for xx such that ∣exβˆ’1βˆ’xx∣<Ο΅\left| \frac{e^x - 1 - x}{x} \right| < \epsilon.

  2. Approximate exe^x using the series expansion for small xx:

ex=1+x+x22+O(x3)e^x = 1 + x + \frac{x^2}{2} + O(x^3)

Thus, exβˆ’1βˆ’xβ‰ˆx22e^x - 1 - x \approx \frac{x^2}{2}, and we have:

∣x22x∣=∣x2∣\left| \frac{\frac{x^2}{2}}{x} \right| = \left| \frac{x}{2} \right|

  1. We now need ∣x2∣<ϡ\left| \frac{x}{2} \right| < \epsilon, which gives:

∣x∣<2ϡ|x| < 2\epsilon

  1. Therefore, we can choose Ξ΄=2Ο΅\delta = 2\epsilon.

For Ο΅=0.5\epsilon = 0.5:

Ξ΄=2Γ—0.5=1.0\delta = 2 \times 0.5 = 1.0

Thus, the corresponding Ξ΄\delta for Ο΅=0.5\epsilon = 0.5 is Ξ΄=1.0\delta = 1.0.


Would you like a more detailed explanation or have any other questions?

Here are 5 related questions to explore:

  1. How do you find limits using the epsilon-delta definition?
  2. What is the Taylor series expansion of exe^x?
  3. How do you solve for Ξ΄\delta in terms of Ο΅\epsilon in general?
  4. What are common limits involving exponential functions?
  5. How does the approximation exβ‰ˆ1+xe^x \approx 1 + x for small xx help in solving limits?

Tip: When using the epsilon-delta definition, approximating complex functions with Taylor series can greatly simplify the problem.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Limits
Epsilon-Delta Definition
Exponential Functions
Taylor Series Expansion

Formulas

lim_(x -> 0) (e^x - 1)/x = 1
|f(x) - L| < Ξ΅
e^x β‰ˆ 1 + x + x^2/2 + O(x^3)

Theorems

Epsilon-Delta Definition of a Limit
Taylor Series Expansion

Suitable Grade Level

Grades 11-12, Early College