Math Problem Statement

lim(x→-2) f(x), where f(x) = (x^2 + 3x - 10) / (x^2 - 4)

Solution

The problem provided is the following:

f(x)=x2+3x10x24=(x+5)(x2)(x2)(x+2)f(x) = \frac{x^2 + 3x - 10}{x^2 - 4} = \frac{(x + 5)(x - 2)}{(x - 2)(x + 2)} You are asked to evaluate the limit:

limx2f(x)\lim_{x \to -2} f(x)

Step-by-Step Solution:

  1. Factor the numerator and the denominator: f(x)=(x+5)(x2)(x2)(x+2)f(x) = \frac{(x + 5)(x - 2)}{(x - 2)(x + 2)}

  2. Cancel the common factor (x2)(x - 2): For x2x \neq 2, we can simplify the function: f(x)=x+5x+2f(x) = \frac{x + 5}{x + 2}

  3. Evaluate the limit: Now, we compute the limit as xx approaches 2-2: limx2x+5x+2\lim_{x \to -2} \frac{x + 5}{x + 2}

  4. Substitute x=2x = -2 directly into the simplified expression: limx2x+5x+2=2+52+2=30\lim_{x \to -2} \frac{x + 5}{x + 2} = \frac{-2 + 5}{-2 + 2} = \frac{3}{0}

  5. Conclusion: Since dividing by zero is undefined, the limit does not exist. However, because we get a positive number divided by zero, we need to analyze the behavior as xx approaches 2-2 from both sides:

    • As x2+x \to -2^+ (from the right), x+2>0x + 2 > 0, leading to ++\infty.
    • As x2x \to -2^- (from the left), x+2<0x + 2 < 0, leading to -\infty.

    Thus, the limit as xx approaches 2-2 is undefined due to a vertical asymptote, but we observe different behaviors from either side.

Final Answer:

limx2f(x)=undefined(positive infinity from the right, negative infinity from the left).\lim_{x \to -2} f(x) = \text{undefined} \quad \text{(positive infinity from the right, negative infinity from the left)}.

Would you like more details or have any questions?


Here are 5 related questions you might consider:

  1. What happens when you evaluate the limit at x=2x = 2?
  2. How can you determine if a function has a vertical asymptote at a given point?
  3. What is the behavior of f(x)f(x) as xx \to \infty?
  4. How would the answer change if you approached a different type of indeterminate form (e.g., 0/00/0)?
  5. Can this function be redefined to remove the discontinuity at x=2x = 2?

Tip: When evaluating limits that result in c0\frac{c}{0}, analyze the behavior of the function from both sides to determine if there is a vertical asymptote or if the limit does not exist.

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Math Problem Analysis

Mathematical Concepts

Limits
Factorization
Asymptotes
Algebra

Formulas

Factorization: (x^2 + bx + c)
Limit evaluation lim(x→c) f(x)

Theorems

Limit theorem
Factorization theorem for quadratics

Suitable Grade Level

Grades 11-12