Math Problem Statement

Consider any function f : ℝ → ℝ, where lim f(x) = 2 and lim f(x) = 3 as x approaches 1. Which of the following statements about f must be true? Statement A: The limit of the function f as x approaches 1 exists. Statement B: The function f is not defined at x = 1.

Solution

The problem in the image presents the function f:RRf : \mathbb{R} \to \mathbb{R} and provides the following information:

limx1f(x)=2andlimx1+f(x)=3\lim_{x \to 1} f(x) = 2 \quad \text{and} \quad \lim_{x \to 1^+} f(x) = 3 Then it asks which of the following statements must be true:

  • Statement A: The limit of the function ff as xx approaches 1 exists.
  • Statement B: The function ff is not defined at x=1x = 1.

Analysis:

  1. Statement A: For the limit of a function limx1f(x)\lim_{x \to 1} f(x) to exist, the left-hand limit limx1f(x)\lim_{x \to 1^-} f(x) and the right-hand limit limx1+f(x)\lim_{x \to 1^+} f(x) must both exist and be equal. Here, the right-hand limit limx1+f(x)=3\lim_{x \to 1^+} f(x) = 3, while limx1f(x)=2\lim_{x \to 1^-} f(x) = 2. Since the left-hand and right-hand limits are not equal, the overall limit limx1f(x)\lim_{x \to 1} f(x) does not exist.

    Therefore, Statement A is false.

  2. Statement B: The problem does not provide direct information about whether the function is defined at x=1x = 1, but since it specifies limits approaching x=1x = 1 from both sides without defining f(1)f(1), we assume that f(1)f(1) may not be defined. This makes Statement B plausible.

Thus, the correct answer is B only.

Would you like further clarification or have any questions?

Here are 5 relative questions to expand on this:

  1. What conditions must be met for a limit to exist at a point?
  2. How do left-hand and right-hand limits relate to the existence of a two-sided limit?
  3. Can a function have different limits from the left and right at the same point?
  4. What does it mean for a function to be undefined at a point?
  5. Can a function be continuous if the limit exists but the function is not defined at that point?

Tip: When evaluating limits, always check whether the left-hand and right-hand limits match before concluding that the limit exists.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Limits
Continuity
Piecewise functions

Formulas

lim (x→a) f(x)
Right-hand limit: lim (x→a+)
Left-hand limit: lim (x→a-)

Theorems

Definition of a limit
Conditions for limit existence

Suitable Grade Level

Grades 11-12 or Early College Level