1. **Problem statement:**
(a) Given that $|f(x) - 3| \leq 4(x - 2)^2$, find $\lim_{x \to 2} f(x)$.
(b) Find the following limits, if they exist:
i. $\lim_{x \to 3} \frac{|x - 3|}{x - 3}$
ii. $\lim_{x \to \infty} \frac{\sqrt{x^4 - 1}}{(x + 1)^2}$
iii. $\lim_{x \to \frac{\pi}{2}} \sin\left(\frac{x}{2} + \sin x\right)$
2. **Step (a):**
We have the inequality $|f(x) - 3| \leq 4(x - 2)^2$.
Recall that if $|f(x) - L| \leq g(x)$ and $\lim_{x \to a} g(x) = 0$, then $\lim_{x \to a} f(x) = L$.
Here, $g(x) = 4(x - 2)^2$ and $\lim_{x \to 2} 4(x - 2)^2 = 0$.
Therefore, by the Squeeze Theorem,
$$\lim_{x \to 2} f(x) = 3.$$
3. **Step (b)(i):**
Evaluate $\lim_{x \to 3} \frac{|x - 3|}{x - 3}$.
Consider the left-hand limit ($x \to 3^-$):
For $x < 3$, $x - 3 < 0$, so $|x - 3| = -(x - 3)$.
Thus,
$$\lim_{x \to 3^-} \frac{|x - 3|}{x - 3} = \lim_{x \to 3^-} \frac{-(x - 3)}{x - 3} = \lim_{x \to 3^-} -1 = -1.$$
Consider the right-hand limit ($x \to 3^+$):
For $x > 3$, $x - 3 > 0$, so $|x - 3| = x - 3$.
Thus,
$$\lim_{x \to 3^+} \frac{|x - 3|}{x - 3} = \lim_{x \to 3^+} \frac{x - 3}{x - 3} = \lim_{x \to 3^+} 1 = 1.$$
Since the left and right limits are not equal, the limit does not exist.
4. **Step (b)(ii):**
Evaluate $\lim_{x \to \infty} \frac{\sqrt{x^4 - 1}}{(x + 1)^2}$.
Rewrite numerator:
$$\sqrt{x^4 - 1} = \sqrt{x^4(1 - \frac{1}{x^4})} = x^2 \sqrt{1 - \frac{1}{x^4}}.$$
Rewrite denominator:
$$(x + 1)^2 = x^2 + 2x + 1 = x^2 \left(1 + \frac{2}{x} + \frac{1}{x^2}\right).$$
So the expression becomes:
$$\frac{x^2 \sqrt{1 - \frac{1}{x^4}}}{x^2 \left(1 + \frac{2}{x} + \frac{1}{x^2}\right)} = \frac{\sqrt{1 - \frac{1}{x^4}}}{1 + \frac{2}{x} + \frac{1}{x^2}}.$$
Taking the limit as $x \to \infty$:
$$\lim_{x \to \infty} \sqrt{1 - \frac{1}{x^4}} = \sqrt{1 - 0} = 1,$$
$$\lim_{x \to \infty} \left(1 + \frac{2}{x} + \frac{1}{x^2}\right) = 1 + 0 + 0 = 1.$$
Therefore,
$$\lim_{x \to \infty} \frac{\sqrt{x^4 - 1}}{(x + 1)^2} = \frac{1}{1} = 1.$$
5. **Step (b)(iii):**
Evaluate $\lim_{x \to \frac{\pi}{2}} \sin\left(\frac{x}{2} + \sin x\right)$.
Since sine is continuous, we can substitute the limit inside:
$$\lim_{x \to \frac{\pi}{2}} \sin\left(\frac{x}{2} + \sin x\right) = \sin\left(\lim_{x \to \frac{\pi}{2}} \left(\frac{x}{2} + \sin x\right)\right).$$
Calculate the inner limit:
$$\lim_{x \to \frac{\pi}{2}} \frac{x}{2} = \frac{\pi}{4},$$
$$\lim_{x \to \frac{\pi}{2}} \sin x = \sin \frac{\pi}{2} = 1.$$
So,
$$\lim_{x \to \frac{\pi}{2}} \left(\frac{x}{2} + \sin x\right) = \frac{\pi}{4} + 1.$$
Therefore,
$$\lim_{x \to \frac{\pi}{2}} \sin\left(\frac{x}{2} + \sin x\right) = \sin\left(\frac{\pi}{4} + 1\right).$$
**Final answers:**
(a) $\lim_{x \to 2} f(x) = 3$
(b)(i) Limit does not exist
(b)(ii) $1$
(b)(iii) $\sin\left(\frac{\pi}{4} + 1\right)$
Limit Evaluation 269F44
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