Limits Tables
1. **Problem Statement:** Find the limits of given functions as $x$ approaches specified values using tables of values and analyze right-hand and left-hand limits for parts (k), (m), and (o).
2. **Limit Definition:** The limit of $f(x)$ as $x$ approaches $a$ is $L$ if for every number $\\epsilon > 0$, there exists a number $\\delta > 0$ such that whenever $0 < |x - a| < \\delta$, then $|f(x) - L| < \\epsilon$.
3. **Right-hand limit ($\lim_{x \to a^+} f(x)$):** The value $f(x)$ approaches as $x$ approaches $a$ from values greater than $a$.
4. **Left-hand limit ($\lim_{x \to a^-} f(x)$):** The value $f(x)$ approaches as $x$ approaches $a$ from values less than $a$.
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**Solutions:**
(a) $\lim_{x \to 0} x = 0$
(b) $\lim_{x \to 1} 2x = 2(1) = 2$
(c) $\lim_{x \to 2} (-x + 1) = -(2) + 1 = -1$
(d) $\lim_{x \to -1} (1 - x) = 1 - (-1) = 2$
(e) $\lim_{x \to 0} (2x - 1) = 2(0) - 1 = -1$
(f) $\lim_{x \to 3} (x - 3) = 3 - 3 = 0$
(g) $\lim_{x \to 2} (3x^2 - 2) = 3(2)^2 - 2 = 3(4) - 2 = 12 - 2 = 10$
(h) $\lim_{x \to 0} (5 - x - x^2) = 5 - 0 - 0 = 5$
(i) $\lim_{x \to 1} (x^3 + 1) = 1^3 + 1 = 2$
(j) $\lim_{x \to 0} (1 - x^2 - x^3) = 1 - 0 - 0 = 1$
(k) $\lim_{x \to 1} \sqrt{x^3 - 1}$
- Evaluate inside the root: $x^3 - 1$
- At $x=1$, $1^3 - 1 = 0$
- Check right-hand limit: For $x > 1$, $x^3 - 1 > 0$, so $\sqrt{x^3 - 1}$ is real and positive.
- Check left-hand limit: For $x < 1$, $x^3 - 1 < 0$, so $\sqrt{x^3 - 1}$ is not real (undefined in reals).
- Therefore, right-hand limit is $0$, left-hand limit does not exist.
- Hence, $\lim_{x \to 1} \sqrt{x^3 - 1}$ does not exist (DNE).
(m) $\lim_{x \to 1} \sqrt{x^4 - x^2 + 1}$
- Evaluate inside the root at $x=1$: $1 - 1 + 1 = 1$
- Since the expression inside the root is continuous and positive near $x=1$, limit is $\sqrt{1} = 1$
- Right-hand and left-hand limits are both $1$.
(o) $\lim_{x \to 1} \frac{1 - x^2}{x + 1}$
- Factor numerator: $1 - x^2 = (1 - x)(1 + x)$
- Simplify expression: $\frac{(1 - x)(1 + x)}{x + 1} = 1 - x$ (for $x \neq -1$)
- Evaluate limit: $1 - 1 = 0$
- Right-hand limit: $\lim_{x \to 1^+} (1 - x) = 0$
- Left-hand limit: $\lim_{x \to 1^-} (1 - x) = 0$
- Limit exists and equals $0$.
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**Final answers:**
(k) Limit does not exist because left-hand limit is undefined.
(m) Limit is $1$.
(o) Limit is $0$.