1. **State the problem:** Find the limit $$\lim_{x \to 3} \frac{x^2 - \frac{1}{9}}{x - 3}$$.
2. **Recall the formula and rules:** When direct substitution leads to an indeterminate form like $$\frac{0}{0}$$, we try to simplify the expression.
3. **Substitute $x=3$ directly:**
$$\frac{3^2 - \frac{1}{9}}{3 - 3} = \frac{9 - \frac{1}{9}}{0} = \frac{\frac{81}{9} - \frac{1}{9}}{0} = \frac{\frac{80}{9}}{0}$$ which is undefined, so simplification is needed.
4. **Rewrite numerator:**
$$x^2 - \frac{1}{9} = \left(x - \frac{1}{3}\right)\left(x + \frac{1}{3}\right)$$ (difference of squares).
5. **Rewrite the limit:**
$$\lim_{x \to 3} \frac{\left(x - \frac{1}{3}\right)\left(x + \frac{1}{3}\right)}{x - 3}$$.
6. **Notice that direct substitution still gives division by zero, so check if numerator can be factored to cancel denominator:**
Since $x - 3$ is not a factor of numerator, try to rewrite numerator as a single fraction:
$$x^2 - \frac{1}{9} = \frac{9x^2 - 1}{9}$$.
7. **Rewrite the limit as:**
$$\lim_{x \to 3} \frac{\frac{9x^2 - 1}{9}}{x - 3} = \lim_{x \to 3} \frac{9x^2 - 1}{9(x - 3)}$$.
8. **Factor numerator $9x^2 - 1$ as difference of squares:**
$$9x^2 - 1 = (3x - 1)(3x + 1)$$.
9. **So the limit becomes:**
$$\lim_{x \to 3} \frac{(3x - 1)(3x + 1)}{9(x - 3)}$$.
10. **Try to factor denominator to cancel with numerator:**
Rewrite $x - 3$ as is, no common factor with numerator.
11. **Since direct substitution still gives division by zero, use algebraic manipulation:**
Rewrite numerator and denominator to express in terms of $(x - 3)$:
$$3x - 1 = 3(x - 3) + 8$$
$$3x + 1 = 3(x - 3) + 10$$
12. **Substitute back:**
$$\frac{(3(x - 3) + 8)(3(x - 3) + 10)}{9(x - 3)}$$.
13. **Expand numerator:**
$$= \frac{9(x - 3)^2 + 54(x - 3) + 80}{9(x - 3)}$$.
14. **Split the fraction:**
$$= \frac{9(x - 3)^2}{9(x - 3)} + \frac{54(x - 3)}{9(x - 3)} + \frac{80}{9(x - 3)} = (x - 3) + 6 + \frac{80}{9(x - 3)}$$.
15. **As $x \to 3$, $(x - 3) \to 0$, but $\frac{80}{9(x - 3)}$ diverges, so limit does not exist as finite number.**
16. **Re-examine original problem:**
The original expression is:
$$\frac{x^2 - \frac{1}{9}}{x - 3}$$
At $x=3$, numerator is $9 - \frac{1}{9} = \frac{80}{9}$, denominator is 0, so limit tends to infinity or negative infinity depending on direction.
17. **Therefore, the limit does not exist (infinite discontinuity).**
**Final answer:** The limit does not exist because the denominator approaches zero while numerator approaches a nonzero constant.
Limit X3 08Bf90
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