Math Problem Statement

Let f be a function of one real variable. Suppose that lim(x -> 4) f(x) = 3. Determine if the following statements are TRUE or FALSE: 1) 3 is in the range/image of f, 2) lim(x -> 4) (f(x))^2 = 9, 3) 4 is in the domain of f.

Solution

Let's analyze the problem from the image:

Problem:

Let ff be a function of one real variable. Suppose that:

limx4f(x)=3.\lim_{x \to 4} f(x) = 3.

You are asked to determine whether the following statements are True or False:

  1. 3 is in the range/image of ff.
  2. limx4(f(x))2=9\lim_{x \to 4} (f(x))^2 = 9.
  3. 4 is in the domain of ff.

Explanation:

  1. 3 is in the range/image of ff:

    • The fact that limx4f(x)=3\lim_{x \to 4} f(x) = 3 does not guarantee that f(4)=3f(4) = 3 or that 3 is in the image of ff. A limit describes the behavior of the function near a point, but f(4)f(4) could be undefined or have a different value.
    • Answer: False.
  2. limx4(f(x))2=9\lim_{x \to 4} (f(x))^2 = 9:

    • If limx4f(x)=3\lim_{x \to 4} f(x) = 3, squaring the limit gives limx4(f(x))2=32=9\lim_{x \to 4} (f(x))^2 = 3^2 = 9.
    • Answer: True.
  3. 4 is in the domain of ff:

    • The limit limx4f(x)=3\lim_{x \to 4} f(x) = 3 implies that f(x)f(x) is defined and behaves well as x4x \to 4, but this does not mean that f(4)f(4) is defined. There are cases where a limit exists, but the function is not defined at the point itself (e.g., removable discontinuity).
    • Answer: False.

Recap:

  • Statement 1: False.
  • Statement 2: True.
  • Statement 3: False.

Would you like any further details or clarifications?

Related questions:

  1. What is the formal definition of a limit?
  2. How do limits relate to continuity of a function?
  3. Can a function have a limit at a point where it is not defined?
  4. What are examples of limits that do not exist?
  5. How does squaring a function affect its limit?

Tip:

Always remember, a limit describes the behavior near a point but does not necessarily reflect the value of the function at that point!

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Math Problem Analysis

Mathematical Concepts

Limits
Function Range
Continuity
Function Domain

Formulas

Limit: lim(x -> a) f(x) = L
Squared limit: lim(x -> a) (f(x))^2 = L^2

Theorems

Limit definition
Limit properties
Continuity and discontinuity

Suitable Grade Level

Undergraduate level (Calculus I)