Math Problem Statement

Complete the table for the function f(x) = (x - 3) / (x^2 - 9) and estimate the limit as x approaches 3.

Solution

In this problem, you are given the function:

f(x)=x3x29f(x) = \frac{x - 3}{x^2 - 9}

and asked to complete the table of values as xx approaches 3. You are also asked to estimate the limit as xx approaches 3 using the function's behavior near that point.

Let's walk through the steps:

  1. Simplify the function: The denominator x29x^2 - 9 can be factored: x29=(x3)(x+3)x^2 - 9 = (x - 3)(x + 3) So the function becomes: f(x)=x3(x3)(x+3)=1x+3,forx3f(x) = \frac{x - 3}{(x - 3)(x + 3)} = \frac{1}{x + 3}, \quad \text{for} \quad x \neq 3 This is valid for all x3x \neq 3, as dividing by zero would otherwise occur at x=3x = 3.

  2. Estimating the limit: As x3x \to 3, the function simplifies to: limx3f(x)=limx31x+3=160.1667\lim_{x \to 3} f(x) = \lim_{x \to 3} \frac{1}{x + 3} = \frac{1}{6} \approx 0.1667 This is the value you are asked to enter in the table where x=3x = 3, which is also verified with the limit at the bottom.

  3. Table values:

    • You are filling in values of f(x)f(x) for x=2.9,2.999,3.001,3.01,3.1x = 2.9, 2.999, 3.001, 3.01, 3.1, and the values are already calculated for some entries:
      • x=2.9x = 2.9, f(x)=0.1695f(x) = 0.1695
      • x=2.999x = 2.999, f(x)=0.1667f(x) = 0.1667
      • x=3.001x = 3.001, f(x)=0.1667f(x) = 0.1667
      • x=3.01x = 3.01, f(x)=0.1669f(x) = 0.1669
      • x=3.1x = 3.1, f(x)=0.4762f(x) = 0.4762
  4. Conclusion: The value of the limit as x3x \to 3 is limx3f(x)=0.1667\lim_{x \to 3} f(x) = 0.1667.

Would you like to see a detailed explanation of any step, or further clarification?

Follow-up Questions:

  1. How does factoring help simplify the given function?
  2. What happens to the function when x=3x = 3?
  3. Why do we check values around x=3x = 3 to estimate the limit?
  4. Can you explain why f(x)f(x) is undefined at x=3x = 3?
  5. How does the limit behave as xx approaches values slightly larger than 3?

Tip:

Always simplify functions as much as possible before calculating limits to avoid unnecessary complications.

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Math Problem Analysis

Mathematical Concepts

Limits
Factoring
Rational Functions

Formulas

f(x) = (x - 3) / (x^2 - 9)
x^2 - 9 = (x - 3)(x + 3)
Limit as x -> 3: lim x->3 (1 / (x + 3))

Theorems

Factoring a Difference of Squares
Limit Theorem

Suitable Grade Level

Grades 10-12