Math Problem Statement

Given ε = 1/2, find all values of δ > 0 so that if |x - 1| < δ then |y - 5| < ε for the function y = 2x + 3.

Solution

The problem you've uploaded asks to find the value of δ>0\delta > 0 such that if x1<δ|x - 1| < \delta, then y5<ϵ|y - 5| < \epsilon where ϵ=12\epsilon = \frac{1}{2} and the function is y=2x+3y = 2x + 3.

Step-by-step approach:

  1. Define the equation: The function given is y=2x+3y = 2x + 3. At x=1x = 1, we can find the value of yy: y(1)=2(1)+3=5y(1) = 2(1) + 3 = 5 So the point (1,5)(1, 5) is the reference point for this limit problem.

  2. Restate the condition: We are given the condition that x1<δ|x - 1| < \delta and we need to ensure that y5<ϵ|y - 5| < \epsilon, where ϵ=12\epsilon = \frac{1}{2}.

  3. Relate y5|y - 5| to x1|x - 1|: y=2x+3soy5=2x+35=2x2=2x1y = 2x + 3 \quad \text{so} \quad |y - 5| = |2x + 3 - 5| = |2x - 2| = 2|x - 1| Thus, y5=2x1|y - 5| = 2|x - 1|.

  4. Use the ϵ\epsilon-condition: We need y5<ϵ|y - 5| < \epsilon. Using the relation y5=2x1|y - 5| = 2|x - 1|, this becomes: 2x1<122|x - 1| < \frac{1}{2} Divide both sides by 2: x1<14|x - 1| < \frac{1}{4}

  5. Conclusion: This implies that δ=14\delta = \frac{1}{4}, since δ\delta is the maximum value for which x1<δ|x - 1| < \delta ensures y5<ϵ|y - 5| < \epsilon.

Answer:

The correct answer is (A) δ=14\delta = \frac{1}{4} or smaller.

Would you like more details on this or have any questions?

Here are 5 related questions for further exploration:

  1. How does the slope of a linear function affect the relationship between δ\delta and ϵ\epsilon?
  2. Can this problem be generalized for any linear function y=mx+by = mx + b?
  3. What happens to δ\delta if ϵ\epsilon is made smaller or larger?
  4. How would the problem change if the function were nonlinear, say y=x2y = x^2?
  5. What role does continuity play in this type of limit problem?

Tip: When solving δ\delta-ϵ\epsilon problems, always relate the change in yy to the change in xx by manipulating the functional relationship.

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Math Problem Analysis

Mathematical Concepts

Calculus
Limits
Delta-Epsilon Definition of a Limit

Formulas

y = 2x + 3
|y - 5| = 2|x - 1|

Theorems

Delta-Epsilon Definition of Limits

Suitable Grade Level

Undergraduate Calculus or Advanced High School Math