1. **State the problem:** Find the limit $$\lim_{x \to -\infty} \sqrt{4x^2 - 6} + \sqrt{x^2 + 1}$$.
2. **Recall the rule:** For limits involving square roots of quadratic expressions as $x \to \pm \infty$, factor out $x^2$ inside the root to simplify.
3. **Rewrite each square root:**
$$\sqrt{4x^2 - 6} = \sqrt{x^2(4 - \frac{6}{x^2})} = |x| \sqrt{4 - \frac{6}{x^2}}$$
$$\sqrt{x^2 + 1} = \sqrt{x^2(1 + \frac{1}{x^2})} = |x| \sqrt{1 + \frac{1}{x^2}}$$
4. **Since $x \to -\infty$, $|x| = -x$. Substitute:**
$$\sqrt{4x^2 - 6} + \sqrt{x^2 + 1} = -x \sqrt{4 - \frac{6}{x^2}} - x \sqrt{1 + \frac{1}{x^2}}$$
5. **Factor out $-x$:**
$$= -x \left( \sqrt{4 - \frac{6}{x^2}} + \sqrt{1 + \frac{1}{x^2}} \right)$$
6. **Evaluate the limit inside the parentheses as $x \to -\infty$:**
$$\lim_{x \to -\infty} \sqrt{4 - \frac{6}{x^2}} = \sqrt{4 - 0} = 2$$
$$\lim_{x \to -\infty} \sqrt{1 + \frac{1}{x^2}} = \sqrt{1 + 0} = 1$$
7. **So the expression behaves like:**
$$-x (2 + 1) = -x \cdot 3$$
8. **Since $x \to -\infty$, $-x \to +\infty$, so:**
$$\lim_{x \to -\infty} \sqrt{4x^2 - 6} + \sqrt{x^2 + 1} = +\infty$$
**Final answer:** The limit diverges to infinity.
Limit Infinity Ca96A9
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