Limits Rational 86Da99
1. **Problem Statement:** Find the left-hand limit, right-hand limit, and the limit at $a=2$ for the function $$f(x) = \frac{x^2 + 3x + 2}{x^2 - 4}$$
2. **Recall the limit definitions:**
- Left-hand limit: $\lim_{x \to a^-} f(x)$ means approaching $a$ from values less than $a$.
- Right-hand limit: $\lim_{x \to a^+} f(x)$ means approaching $a$ from values greater than $a$.
- Limit at $a$: $\lim_{x \to a} f(x)$ exists only if left and right limits are equal.
3. **Simplify the function:**
Factor numerator and denominator:
$$x^2 + 3x + 2 = (x+1)(x+2)$$
$$x^2 - 4 = (x-2)(x+2)$$
So,
$$f(x) = \frac{(x+1)(x+2)}{(x-2)(x+2)}$$
For $x \neq -2$, this simplifies to:
$$f(x) = \frac{x+1}{x-2}$$
4. **Evaluate the limits at $a=2$: **
- Left-hand limit:
$$\lim_{x \to 2^-} f(x) = \lim_{x \to 2^-} \frac{x+1}{x-2}$$
As $x$ approaches 2 from the left, denominator $x-2$ approaches 0 negative, numerator $x+1$ approaches 3 positive.
So,
$$\lim_{x \to 2^-} f(x) = -\infty$$
- Right-hand limit:
$$\lim_{x \to 2^+} f(x) = \lim_{x \to 2^+} \frac{x+1}{x-2}$$
As $x$ approaches 2 from the right, denominator $x-2$ approaches 0 positive, numerator $x+1$ approaches 3 positive.
So,
$$\lim_{x \to 2^+} f(x) = +\infty$$
- Since left and right limits are not equal, the limit at $x=2$ does not exist:
$$\lim_{x \to 2} f(x) \text{ does not exist}$$
**Final answers:**
$$\lim_{x \to 2^-} f(x) = -\infty$$
$$\lim_{x \to 2^+} f(x) = +\infty$$
$$\lim_{x \to 2} f(x) \text{ does not exist}$$