Math Problem Statement

lim(x -> 2) (x^3 - 2x^2) / (x^2 - 4)

Solution

The given expression is:

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

Let's solve this step by step.

Step 1: Substitute x=2x = 2 directly into the expression.

If we substitute x=2x = 2 directly into the expression:

(232×22)(224)=(88)(44)=00\frac{(2^3 - 2 \times 2^2)}{(2^2 - 4)} = \frac{(8 - 8)}{(4 - 4)} = \frac{0}{0}

We get the indeterminate form 00\frac{0}{0}. This means we need to apply algebraic simplification or use L'Hôpital's Rule.

Step 2: Factor the denominator and numerator.

Factor the denominator first:

x24=(x2)(x+2)x^2 - 4 = (x - 2)(x + 2)

Next, factor the numerator:

x32x2=x2(x2)x^3 - 2x^2 = x^2(x - 2)

Step 3: Simplify the expression.

Now rewrite the limit with the factored terms:

limx2x2(x2)(x2)(x+2)\lim_{{x \to 2}} \frac{x^2(x - 2)}{(x - 2)(x + 2)}

We can cancel out the common factor (x2)(x - 2) from both the numerator and the denominator:

limx2x2x+2\lim_{{x \to 2}} \frac{x^2}{x + 2}

Step 4: Substitute x=2x = 2 into the simplified expression.

Now that we have eliminated the indeterminate form, we substitute x=2x = 2 into the simplified expression:

222+2=44=1\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

Would you like further details or explanations?

Here are 5 related questions to expand on this concept:

  1. What is L'Hôpital's Rule, and when is it used to solve limits?
  2. How do you factor polynomials like x32x2x^3 - 2x^2?
  3. What other techniques can be used to simplify indeterminate forms like 00\frac{0}{0}?
  4. Can limits involving higher-order polynomials also be simplified by factoring?
  5. How does the behavior of limits help in understanding continuity of functions?

Tip: Always check for the possibility of factoring polynomials when you encounter indeterminate forms like 00\frac{0}{0} in limits.

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Math Problem Analysis

Mathematical Concepts

Limits
Factoring Polynomials
Indeterminate Forms

Formulas

lim(x -> a) f(x)/g(x)
Factoring: a^2 - b^2 = (a - b)(a + b)

Theorems

L'Hôpital's Rule

Suitable Grade Level

Grade 10-12