Math Problem Statement

Determine for which values of x = a the limit of f(x) exists but f is not continuous at x = a. Additionally, determine for which values of x = a the function is continuous but not differentiable at x = a.

Solution

Looking at the graph, let's address the two parts of the question:

(a) Limit Exists but Function is Not Continuous

For this part, we need to find a point where the limit of f(x)f(x) exists, but f(x)f(x) is not continuous at x=ax = a. This happens when the left-hand and right-hand limits of f(x)f(x) as xax \to a are equal, but f(a)f(a) is not defined or differs from the limit.

In the graph:

  • At x=2x = 2, the limit exists from both sides, but there is a hole at x=2x = 2, meaning f(2)f(2) is not continuous.

This is why the correct answer to (a) is x=2x = 2, which you correctly answered.


(b) Function is Continuous but Not Differentiable

For this part, we are looking for a point where the function is continuous but has a sharp corner, cusp, or vertical tangent line, making it non-differentiable at x=ax = a.

From the graph:

  • At x=1x = 1, the function is continuous, but there is a sharp corner, indicating that ff is not differentiable at this point. However, x=1x = 1 seems like it should be correct, but it was marked wrong.

It is possible that there is another point where this condition holds. I would suggest looking at x=3x = 3, where the function has a sharp corner as well. Thus, x=3x = 3 might be the correct answer instead.


Do you need further clarification or details? Here are 5 related questions for deeper understanding:

  1. Why is a function not differentiable at a sharp corner?
  2. How can we verify the continuity of a function at a point?
  3. What is the relationship between differentiability and continuity?
  4. Can you identify other points on the graph where the function might be discontinuous?
  5. What is the significance of a limit existing but the function not being continuous?

Tip: When analyzing continuity and differentiability, always check for gaps, jumps, or sharp turns in the graph.

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Math Problem Analysis

Mathematical Concepts

Limits
Continuity
Differentiability
Sharp Corners
Piecewise Functions

Formulas

Left-hand and right-hand limits
Limit definition
Continuity condition: lim x→a f(x) = f(a)
Differentiability conditions

Theorems

Fundamental Theorem of Calculus
Conditions for Differentiability

Suitable Grade Level

Grades 11-12