Math Problem Statement

Solve this and explain it to me

Suppose we know lim(x→∞) f(x) = 2. Which of the following statements must be true? Check all that are true: A. lim(x→−∞) f(x) = −2 B. lim(x→−∞) f(x) = 2 C. f(x) is continuous at x=∞ D. f(x) has a horizontal asymptote at y=2 E. As x gets very large, f(x) gets close to 2 F. f(x) has a vertical asymptote at x=2 G. f(x) is never equal to 2.

Solution

The question asks to determine which statements must be true based on the given information that:

limxf(x)=2\lim_{x \to \infty} f(x) = 2

Let's analyze each option:

A. limxf(x)=2\lim_{x \to -\infty} f(x) = -2

This is unrelated to the provided information because the given limit only specifies what happens as xx \to \infty (positive infinity), not as xx \to -\infty (negative infinity). Therefore, A is not necessarily true.


B. limxf(x)=2\lim_{x \to -\infty} f(x) = 2

Again, this concerns the behavior of f(x)f(x) as xx \to -\infty, but the problem only tells us about the limit as xx \to \infty. There’s no guarantee that the function behaves the same way in the negative direction. Thus, B is not necessarily true.


C. f(x)f(x) is continuous at x=x = \infty

Continuity at x=x = \infty is not a meaningful concept because continuity applies to finite values of xx, and we don't assess continuity at infinity. Therefore, C is false.


D. f(x)f(x) has a horizontal asymptote at y=2y = 2

The limit limxf(x)=2\lim_{x \to \infty} f(x) = 2 means that as xx gets very large, f(x)f(x) approaches 2. This is the definition of a horizontal asymptote at y=2y = 2. Hence, D is true.


E. As xx gets very large, f(x)f(x) gets close to 2

This directly follows from the limit definition limxf(x)=2\lim_{x \to \infty} f(x) = 2. As xx becomes very large, f(x)f(x) approaches 2. Thus, E is true.


F. f(x)f(x) has a vertical asymptote at x=2x = 2

A vertical asymptote means that the function becomes unbounded as xx approaches a certain value, but this statement doesn’t follow from the given information. The limit tells us about the behavior as xx \to \infty, not about any vertical asymptotes. Therefore, F is false.


G. f(x)f(x) is never equal to 2

The limit limxf(x)=2\lim_{x \to \infty} f(x) = 2 only means that f(x)f(x) approaches 2 as xx becomes large, but it doesn’t imply that f(x)f(x) can never actually equal 2. Thus, G is false.


Conclusion:

The correct answers are:

  • D: f(x)f(x) has a horizontal asymptote at y=2y = 2.
  • E: As xx gets very large, f(x)f(x) gets close to 2.

Would you like more details on any part of the explanation?

Related Questions:

  1. What is the formal definition of a horizontal asymptote?
  2. Can a function have different limits as xx \to \infty and xx \to -\infty?
  3. How does continuity relate to limits?
  4. What is the difference between horizontal and vertical asymptotes?
  5. How can we verify if a function actually equals its limit value at infinity?

Tip: Horizontal asymptotes describe the end behavior of a function as xx approaches infinity or negative infinity, indicating that the function gets arbitrarily close to a particular value but doesn't necessarily reach it.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Limits
Asymptotes
Continuity

Formulas

lim(x→∞) f(x)
Horizontal Asymptote Definition

Theorems

Limit Theorem
Horizontal Asymptote Theorem

Suitable Grade Level

Grades 10-12