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 $|f(x) - 3| \leq 4(x - 2)^2$.
As $x \to 2$, note that $(x - 2)^2 \to 0$.
By the Squeeze Theorem, since $|f(x) - 3|$ is squeezed by $4(x - 2)^2$ which tends to 0, it follows that
$$\lim_{x \to 2} |f(x) - 3| = 0,$$
which implies
$$\lim_{x \to 2} f(x) = 3.$$
3. **Step (b)(i):**
Consider $\lim_{x \to 3} \frac{|x - 3|}{x - 3}$.
For $x > 3$, $|x - 3| = x - 3$, so the expression becomes
$$\frac{x - 3}{x - 3} = 1.$$
For $x < 3$, $|x - 3| = -(x - 3)$, so the expression becomes
$$\frac{-(x - 3)}{x - 3} = -1.$$
Since the left-hand limit is $-1$ and the right-hand limit is $1$, 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:
$$(x + 1)^2 = x^2 + 2x + 1.$$
Divide numerator and denominator by $x^2$:
$$\frac{x^2 \sqrt{1 - \frac{1}{x^4}}}{x^2 + 2x + 1} = \frac{\sqrt{1 - \frac{1}{x^4}}}{1 + \frac{2}{x} + \frac{1}{x^2}}.$$
As $x \to \infty$, terms with $\frac{1}{x}$ and higher powers go to 0, so
$$\lim_{x \to \infty} \frac{\sqrt{1 - \frac{1}{x^4}}}{1 + \frac{2}{x} + \frac{1}{x^2}} = \frac{\sqrt{1 - 0}}{1 + 0 + 0} = 1.$$
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:
$$\sin\left(\lim_{x \to \frac{\pi}{2}} \left(\frac{x}{2} + \sin x\right)\right) = \sin\left(\frac{\pi}{4} + \sin \frac{\pi}{2}\right).$$
Calculate inside:
$$\sin \frac{\pi}{2} = 1,$$
so
$$\frac{\pi}{4} + 1.$$
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 5Ae365
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