Math Problem Statement

Find all values x = a where the function is discontinuous. For each value of x, give the limit of the function as x approaches a. The function is f(x) = (x^2 - 4)/(x - 2).

Solution

Let's analyze the function f(x)=x24x2f(x) = \frac{x^2 - 4}{x - 2} and find where it is discontinuous.

  1. Simplifying the function: The numerator x24x^2 - 4 is a difference of squares, so it can be factored: f(x)=(x2)(x+2)x2f(x) = \frac{(x - 2)(x + 2)}{x - 2} For x2x \neq 2, we can cancel the (x2)(x - 2) terms: f(x)=x+2forx2f(x) = x + 2 \quad \text{for} \quad x \neq 2 However, when x=2x = 2, the original expression is undefined because of division by zero. This means the function has a removable discontinuity at x=2x = 2.

  2. Evaluating the limit as x2x \to 2: Since f(x)=x+2f(x) = x + 2 for x2x \neq 2, we can find the limit as xx approaches 2: limx2f(x)=limx2(x+2)=4\lim_{x \to 2} f(x) = \lim_{x \to 2} (x + 2) = 4 Therefore, the limit exists at x=2x = 2, but the function is not defined there.

  3. Conclusion: The function is discontinuous at x=2x = 2, with a removable discontinuity because the limit exists but the function is undefined at that point.

Based on this, the correct choice is likely A, where the function is discontinuous at the single value x=2x = 2, and the limit is 4.

Would you like more details or have any questions about this? Here are some additional related questions you might find helpful:

  1. What are the different types of discontinuities (removable, jump, infinite)?
  2. How do you distinguish between a removable discontinuity and a non-removable one?
  3. Can a function have more than one discontinuity point?
  4. How does factoring help in identifying discontinuities?
  5. What role do limits play in determining the behavior of functions at points of discontinuity?

Tip: Always check if a discontinuity is removable by simplifying the function, as factoring can reveal hidden behavior at certain points.

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Math Problem Analysis

Mathematical Concepts

Discontinuities
Limits
Factoring
Algebra

Formulas

Difference of squares: a^2 - b^2 = (a - b)(a + b)
Limit of a function

Theorems

Limit Definition
Removable Discontinuity Theorem

Suitable Grade Level

Grades 10-12