Math Problem Statement

lim_{x \to 2} (x^2 - 4)/(x-2)

Solution

The given limit is:

limx2x24x2.\lim_{x \to 2} \frac{x^2 - 4}{x - 2}.

Step 1: Simplify the expression

The numerator x24x^2 - 4 is a difference of squares, so we can factorize it as: x24=(x2)(x+2).x^2 - 4 = (x - 2)(x + 2).

Substitute this back into the expression: x24x2=(x2)(x+2)x2.\frac{x^2 - 4}{x - 2} = \frac{(x - 2)(x + 2)}{x - 2}.

Step 2: Cancel common terms

For x2x \neq 2, the x2x - 2 terms cancel out, leaving: (x2)(x+2)x2=x+2.\frac{(x - 2)(x + 2)}{x - 2} = x + 2.

Step 3: Evaluate the limit

Since the simplified expression is x+2x + 2, the limit as x2x \to 2 is: limx2(x+2)=2+2=4.\lim_{x \to 2} (x + 2) = 2 + 2 = 4.

Final Answer:

limx2x24x2=4.\lim_{x \to 2} \frac{x^2 - 4}{x - 2} = 4.


Would you like further details or have any questions? Here are some related questions for further exploration:

  1. What happens if you don't cancel the common factor and directly substitute x=2x = 2?
  2. How does this relate to the concept of removable discontinuities?
  3. Can you describe why this limit exists despite the original function being undefined at x=2x = 2?
  4. What would the limit be if x24x^2 - 4 were replaced with another polynomial like x25x+6x^2 - 5x + 6?
  5. How does factoring simplify the process of finding limits in rational functions?

Tip: Always check if the numerator and denominator can be factored to simplify the evaluation of limits, especially when direct substitution results in an indeterminate form like 0/00/0.

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Math Problem Analysis

Mathematical Concepts

Limits
Factoring Polynomials
Difference of Squares

Formulas

Difference of Squares: a^2 - b^2 = (a - b)(a + b)
Simplification of Rational Functions

Theorems

Limit Laws
Removable Discontinuities

Suitable Grade Level

Grades 10-12