Math Problem Statement

Finding 6 In Exercises 43-48, find the limit L. Then find S such that |/(r) - L| < e whenever 0 < [r - c| < 8 for *) € = 0.01 and (b) € = 0.005 45. lim as x goes to 2 of (x^2-3)

Solution

Let's analyze the problem and find the limit LL and δ\delta for the given function and conditions.

Step 1: Find the Limit LL

We are asked to find the limit of the function f(x)=x23f(x) = x^2 - 3 as xx approaches 2:

limx2(x23)\lim_{x \to 2} (x^2 - 3)

To find this limit, we can substitute x=2x = 2 into the function:

f(2)=223=43=1f(2) = 2^2 - 3 = 4 - 3 = 1

Thus, the limit LL is 1:

L=1L = 1

Step 2: Find δ\delta for Given ϵ\epsilon Values

We need to find δ\delta such that:

f(x)L<ϵwhenever0<x2<δ|f(x) - L| < \epsilon \quad \text{whenever} \quad 0 < |x - 2| < \delta

(a) For ϵ=0.01\epsilon = 0.01

Let's express the condition f(x)L<ϵ|f(x) - L| < \epsilon:

x231<0.01|x^2 - 3 - 1| < 0.01

Simplify the expression inside the absolute value:

x24<0.01|x^2 - 4| < 0.01

We can factor this as:

(x2)(x+2)<0.01|(x - 2)(x + 2)| < 0.01

To relate this to x2|x - 2|, consider:

x2x+2<0.01|x - 2| \cdot |x + 2| < 0.01

Now, assume δ\delta is small enough such that x2<1|x - 2| < 1. Then, 1<x<31 < x < 3, and consequently, 3<x+2<53 < x + 2 < 5. Thus, x+2<5|x + 2| < 5.

Using this bound:

x25<0.01|x - 2| \cdot 5 < 0.01

x2<0.015=0.002|x - 2| < \frac{0.01}{5} = 0.002

Therefore, for ϵ=0.01\epsilon = 0.01, we can choose δ=0.002\delta = 0.002.

(b) For ϵ=0.005\epsilon = 0.005

Repeat the process for ϵ=0.005\epsilon = 0.005:

x24<0.005|x^2 - 4| < 0.005

(x2)(x+2)<0.005|(x - 2)(x + 2)| < 0.005

Again, using x+2<5|x + 2| < 5:

x25<0.005|x - 2| \cdot 5 < 0.005

x2<0.0055=0.001|x - 2| < \frac{0.005}{5} = 0.001

Thus, for ϵ=0.005\epsilon = 0.005, we can choose δ=0.001\delta = 0.001.

Summary

  1. Limit LL: 11
  2. δ\delta for ϵ=0.01\epsilon = 0.01: 0.0020.002
  3. δ\delta for ϵ=0.005\epsilon = 0.005: 0.0010.001

Would you like more details, or do you have any questions?

Related Questions

  1. How do we handle limits when the function has a discontinuity at the point of interest?
  2. What is the formal definition of a limit using ϵ\epsilon and δ\delta?
  3. How do we determine δ\delta when xc<δ|x - c| < \delta for more complex functions?
  4. How do limits relate to derivatives?
  5. What happens to the limit if xx \to \infty or xx \to -\infty?

Tip

When finding δ\delta for a given ϵ\epsilon, it helps to estimate bounds on x+c|x + c| or any expression to simplify the inequality.

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Math Problem Analysis

Mathematical Concepts

Limits
Absolute Value
Epsilon-Delta Definition

Formulas

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Theorems

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Suitable Grade Level

College Level