Math Problem Statement

lim(x→2) [(x^3 - 2x^2) / (x^2 - 4)]

Solution

The given limit is:

limx2x32x2x24\lim_{x \to 2} \frac{x^3 - 2x^2}{x^2 - 4}

Step 1: Simplify the expression

Notice that the denominator x24x^2 - 4 can be factored as: x24=(x2)(x+2)x^2 - 4 = (x - 2)(x + 2)

The numerator x32x2x^3 - 2x^2 can be factored as: x32x2=x2(x2)x^3 - 2x^2 = x^2(x - 2)

Now the expression becomes: x32x2x24=x2(x2)(x2)(x+2)\frac{x^3 - 2x^2}{x^2 - 4} = \frac{x^2(x - 2)}{(x - 2)(x + 2)}

Step 2: Cancel common terms

For x2x \neq 2, we can cancel (x2)(x - 2) from the numerator and denominator: x2(x2)(x2)(x+2)=x2x+2,x2\frac{x^2(x - 2)}{(x - 2)(x + 2)} = \frac{x^2}{x + 2}, \quad x \neq 2

Step 3: Substitute x=2x = 2

Substitute x=2x = 2 into the simplified expression: x2x+2=222+2=44=1\frac{x^2}{x + 2} = \frac{2^2}{2 + 2} = \frac{4}{4} = 1

Final Answer:

limx2x32x2x24=1\lim_{x \to 2} \frac{x^3 - 2x^2}{x^2 - 4} = 1

Let me know if you'd like further clarification or a detailed explanation of any step.


Here are some related questions to expand your understanding:

  1. How do we handle limits involving indeterminate forms such as 00\frac{0}{0}?
  2. What are other techniques for solving limits besides factoring?
  3. How does L'Hôpital's Rule apply to this problem?
  4. Can this limit be solved using numerical approximation? How?
  5. What happens if x2x \to -2 instead of x2x \to 2?

Tip: Always check for factorizations or common terms before applying more advanced limit-solving techniques like L'Hôpital's Rule.

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Math Problem Analysis

Mathematical Concepts

Limits
Factoring
Indeterminate Forms

Formulas

Factorization of polynomials
Simplification of rational expressions

Theorems

Limit laws
Indeterminate forms (0/0)

Suitable Grade Level

Grades 11-12