Function Evaluation Domain
1. **Problem 01**: Given the function $f(x) = 3x^2 - x + 3$, find the following values:
(a) $f(2)$
Calculate by substituting $x=2$:
$$f(2) = 3(2)^2 - 2 + 3 = 3 \times 4 - 2 + 3 = 12 - 2 + 3 = 13$$
(b) $f(-2)$
Substitute $x = -2$:
$$f(-2) = 3(-2)^2 - (-2) + 3 = 3 \times 4 + 2 + 3 = 12 + 2 + 3 = 17$$
(c) $f(t)$
Substitute $x = t$ (variable):
$$f(t) = 3t^2 - t + 3$$
(d) $f(2x - 1)$
Replace $x$ by $2x - 1$:
$$f(2x-1) = 3(2x-1)^2 - (2x-1) + 3$$
Expand $(2x-1)^2 = 4x^2 - 4x + 1$:
$$= 3(4x^2 - 4x + 1) - 2x + 1 + 3 = 12x^2 - 12x + 3 - 2x + 1 + 3$$
Combine like terms:
$$= 12x^2 - 14x + 7$$
(e) Compute $f(a^2)$ and $[f(a)]^2$:
$f(a^2)$:
$$= 3(a^2)^2 - a^2 + 3 = 3a^4 - a^2 + 3$$
$[f(a)]^2$:
First find $f(a)$:
$$f(a) = 3a^2 - a + 3$$
Square it:
$$[f(a)]^2 = (3a^2 - a + 3)^2$$
Expand using $(A-B+C)^2 = A^2 - 2AB + 2AC + B^2 - 2BC + C^2$ method or FOIL:
$$= (3a^2)^2 - 2 \times 3a^2 \times a + 2 \times 3a^2 \times 3 + (-a)^2 - 2 \times (-a) \times 3 + 3^2$$
Calculate:
$$= 9a^4 - 6a^3 + 18a^2 + a^2 + 6a + 9 = 9a^4 - 6a^3 + 19a^2 + 6a + 9$$
(f) Find the expression $$\frac{f(x)-f(1)}{x-1}$$
Calculate $f(1)$:
$$f(1) = 3(1)^2 - 1 + 3 = 3 - 1 + 3 = 5$$
Substitute in the numerator:
$$\frac{(3x^2 - x + 3) - 5}{x-1} = \frac{3x^2 - x + 3 - 5}{x-1} = \frac{3x^2 - x - 2}{x-1}$$
Factor numerator:
$$3x^2 - x - 2 = (3x + 2)(x - 1)$$
Simplify:
$$\frac{(3x + 2)(x-1)}{x-1} = 3x + 2\quad \text{for } x \neq 1$$
2. **Problem 02**: Find domain of each function:
(a) $$f(x) = \frac{5x + 4}{x^2 + 3x + 2}$$
The denominator must be nonzero:
$$x^2 + 3x + 2 \neq 0$$
Factor denominator:
$$(x + 1)(x + 2) \neq 0$$
Exclude $x = -1$ and $x = -2$, so:
$$\text{Domain} = \{x \in \mathbb{R} : x \neq -1, x \neq -2\}$$
(b) $$G(u) = \sqrt{u} + \sqrt{4 - u}$$
Radicands must be nonnegative:
$$u \geq 0$$
$$4 - u \geq 0 \Rightarrow u \leq 4$$
Combine:
$$0 \leq u \leq 4$$
(c) $$f(x) = \sqrt{5 - 5x - x^2}$$
Radicand must be nonnegative:
$$5 - 5x - x^2 \geq 0$$
Rewrite:
$$-x^2 - 5x + 5 \geq 0$$
Multiply both sides by $-1$ (reverse inequality):
$$x^2 + 5x - 5 \leq 0$$
Find roots using quadratic formula:
$$x = \frac{-5 \pm \sqrt{25 + 20}}{2} = \frac{-5 \pm \sqrt{45}}{2} = \frac{-5 \pm 3\sqrt{5}}{2}$$
The parabola opens upwards, so inequality holds between roots:
$$\frac{-5 - 3\sqrt{5}}{2} \leq x \leq \frac{-5 + 3\sqrt{5}}{2}$$
3. **Problem 03**: Based on the described graph:
(a) State $f(-1)$:
Graph starts above $y=1$ on left, so estimate $f(-1) \approx$ value $>1$ (roughly 2).
(b) Estimate $f(2)$:
Graph slightly above $y=1$ at $x=1$ and levels off, so $f(2) \approx 1.5$ (approximate).
(c) Values of $x$ where $f(x) = 2$:
From graph, $f(x)$ is 2 near $x = -1$, and possibly another value after $1$, say $x \approx 1.5$.
(d) Values where $f(x) = 0$:
Graph crosses $y=0$ near $x=0$, so $f(0) = 0$, estimate roots near $x=0$.
(e) Domain and Range:
Domain is all real numbers (graph stretches left and right).
Range includes values from minimum below zero to above 2, that is
$$\text{Range} = [\text{minimum} < 0, \text{maximum} > 2]$$
Final summarized answers are above with all steps shown.