Math Problem Statement

Suppose short dash x squared plus 4 x minus 1 less or equal than f left parenthesis x right parenthesis less or equal than x squared minus 4 x plus 7 for all x values near x equals 2, except possibly at 2.

Evaluate limit as x rightwards arrow 2 of f left parenthesis x right parenthesis.

A.)

limit as x rightwards arrow 2 of f left parenthesis x right parenthesis equals 11

B.)

limit as x rightwards arrow 2 of f left parenthesis x right parenthesis equals 7

C.)

limit as x rightwards arrow 2 of f left parenthesis x right parenthesis space d o e s space n o t space e x i s t

D.)

limit as x rightwards arrow 2 of f left parenthesis x right parenthesis equals 3

Solution

We are given the inequality:

x2+4x1f(x)x24x+7for allxnearx=2,except possibly atx=2.x^2 + 4x - 1 \leq f(x) \leq x^2 - 4x + 7 \quad \text{for all} \, x \, \text{near} \, x = 2, \text{except possibly at} \, x = 2.

We are asked to evaluate the limit of f(x)f(x) as x2x \to 2.

Step 1: Evaluate the two bounding functions at x=2x = 2

First, we calculate the values of the two bounding functions at x=2x = 2:

  • For the left-hand side function x2+4x1x^2 + 4x - 1: (2)2+4(2)1=4+81=11.(2)^2 + 4(2) - 1 = 4 + 8 - 1 = 11.

  • For the right-hand side function x24x+7x^2 - 4x + 7: (2)24(2)+7=48+7=3.(2)^2 - 4(2) + 7 = 4 - 8 + 7 = 3.

So, we now have:

3f(x)11for allxnear2.3 \leq f(x) \leq 11 \quad \text{for all} \, x \, \text{near} \, 2.

Step 2: Apply the Squeeze Theorem

The Squeeze Theorem tells us that if f(x)f(x) is squeezed between two functions that both approach the same limit as x2x \to 2, then limx2f(x)\lim_{x \to 2} f(x) must also approach that same limit.

  • The left-hand side function x2+4x1x^2 + 4x - 1 approaches 11 as x2x \to 2.
  • The right-hand side function x24x+7x^2 - 4x + 7 approaches 3 as x2x \to 2.

Since the two bounding functions do not approach the same value at x=2x = 2, the Squeeze Theorem does not apply, and we cannot conclude that f(x)f(x) will approach a single value.

Thus, the limit does not exist.

Final Answer:

The correct answer is:

C.) limit as x2x \to 2 of f(x)f(x) does not exist.


If you'd like further clarification, feel free to ask!

Here are some related questions to expand on the topic:

  1. What is the Squeeze Theorem and how is it used in limit evaluation?
  2. How do we evaluate the limit of a function when it's bounded by two other functions?
  3. What happens if two bounding functions approach different limits at the same point?
  4. What are other methods to evaluate limits of functions when direct substitution doesn’t work?
  5. How do we apply the definition of a limit to confirm whether a limit exists?

Tip: Always check if the two bounding functions approach the same limit before applying the Squeeze Theorem!

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Math Problem Analysis

Mathematical Concepts

Limit Evaluation
Inequalities
Squeeze Theorem

Formulas

Squeeze Theorem
Limit of a function

Theorems

Squeeze Theorem

Suitable Grade Level

Grades 11-12