Math Problem Statement

Use the given graph of f to find a number δ such that if 0 < |x – 3| < δ then |f(x) – 2| < 0.5.

Solution

This graph asks to find a number δ\delta such that for 0<x3<δ0 < |x - 3| < \delta, it satisfies the condition f(x)2<0.5|f(x) - 2| < 0.5. This problem deals with the concept of limits, specifically the ϵδ\epsilon-\delta definition of a limit.

Step-by-step approach:

  1. Understanding the condition f(x)2<0.5|f(x) - 2| < 0.5:

    • This inequality implies that the function values f(x)f(x) should stay within the range 1.5<f(x)<2.51.5 < f(x) < 2.5 (since 20.5=1.52 - 0.5 = 1.5 and 2+0.5=2.52 + 0.5 = 2.5).
  2. Identifying the xx-range for f(x)f(x) in 1.5<f(x)<2.51.5 < f(x) < 2.5:

    • Looking at the graph, the function reaches the value f(x)=2f(x) = 2 at x=3x = 3.
    • From the graph, observe that when f(x)f(x) is between 1.5 and 2.5, the corresponding xx-values seem to range from approximately 2.62.6 to 3.83.8.
  3. Determining δ\delta:

    • The condition 0<x3<δ0 < |x - 3| < \delta means that the value of xx is within a distance δ\delta from 3.
    • From the graph, we see that the function values are between 1.5 and 2.5 when xx is between 2.6 and 3.8.
    • Therefore, δ\delta would be the smallest of the distances from 3 to 2.6 or 3 to 3.8.
    • The distances are 32.6=0.4|3 - 2.6| = 0.4 and 33.8=0.8|3 - 3.8| = 0.8. Hence, the smallest δ\delta is 0.40.4.

Conclusion:

The value of δ\delta that satisfies the condition is δ=0.4\delta = 0.4.

Would you like a more detailed breakdown of the concept or have any further questions?

Here are five relative questions that can expand your understanding:

  1. How does the ϵδ\epsilon-\delta definition of limits work in general?
  2. What is the significance of the ϵ\epsilon value in these problems?
  3. How would the result change if we asked for f(x)2<0.1|f(x) - 2| < 0.1?
  4. What are the key differences between left-hand and right-hand limits?
  5. How do we handle ϵδ\epsilon-\delta problems where the function is not continuous?

Tip: Always visualize or sketch the neighborhood of the limit point when dealing with ϵδ\epsilon-\delta problems—it can greatly help with interpreting the conditions.

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Math Problem Analysis

Mathematical Concepts

Limits
Epsilon-Delta Definition

Formulas

|x - a| < δ
|f(x) - L| < ε

Theorems

Epsilon-Delta Definition of Limits

Suitable Grade Level

College-level Calculus