Responder
The domain of \( f + g \) is all real numbers, which can be written as \( (-\infty, \infty) \).
Solución
Let's analyze the given functions and perform the required operations step by step.
### Given Functions:
- \( f(x) = 6 - x^2 \)
- \( g(x) = x^2 + 4x - 32 \)
### 1. **Sum: \( f + g \)**
\[
\begin{align*}
f + g &= (6 - x^2) + (x^2 + 4x - 32) \\
&= 6 - x^2 + x^2 + 4x - 32 \\
&= 4x - 26
\end{align*}
\]
**Simplified Form:**
\[
f + g = 4x - 26
\]
### 2. **Difference: \( f - g \)**
\[
\begin{align*}
f - g &= (6 - x^2) - (x^2 + 4x - 32) \\
&= 6 - x^2 - x^2 - 4x + 32 \\
&= -2x^2 - 4x + 38
\end{align*}
\]
**Simplified Form:**
\[
f - g = -2x^2 - 4x + 38
\]
### 3. **Product: \( f \cdot g \)**
\[
\begin{align*}
f \cdot g &= (6 - x^2)(x^2 + 4x - 32) \\
&= 6(x^2) + 6(4x) + 6(-32) - x^2(x^2) - x^2(4x) - x^2(-32) \\
&= 6x^2 + 24x - 192 - x^4 - 4x^3 + 32x^2 \\
&= -x^4 - 4x^3 + 38x^2 + 24x - 192
\end{align*}
\]
**Simplified Form:**
\[
f \cdot g = -x^4 - 4x^3 + 38x^2 + 24x - 192
\]
### 4. **Quotient: \( \frac{f}{g} \)**
\[
\frac{f}{g} = \frac{6 - x^2}{x^2 + 4x - 32}
\]
**Factorization:**
- **Numerator:** \( 6 - x^2 = -(x^2 - 6) \) (cannot be factored further over real numbers)
- **Denominator:**
\[
x^2 + 4x - 32 = (x - 4)(x + 8)
\]
**Simplified Form:**
\[
\frac{f}{g} = \frac{6 - x^2}{(x - 4)(x + 8)}
\]
(No further simplification is possible.)
### 5. **Determining the Domain**
- **Domain of \( f(x) \):** All real numbers, since it's a polynomial.
- **Domain of \( g(x) \):** All real numbers, since it's a polynomial.
- **Domain of \( f + g \), \( f - g \), and \( f \cdot g \):** All real numbers, as these operations on polynomials result in polynomials.
- **Domain of \( \frac{f}{g} \):** All real numbers except where \( g(x) = 0 \).
**Finding where \( g(x) = 0 \):**
\[
x^2 + 4x - 32 = 0 \\
x = \frac{-4 \pm \sqrt{16 + 128}}{2} = \frac{-4 \pm 12}{2} \\
x = 4 \quad \text{or} \quad x = -8
\]
**Thus, the domain of \( \frac{f}{g} \) is:**
\[
\mathbb{R} \setminus \{ -8, 4 \}
\]
### 6. **Multiple Choice Question:**
**What is the domain of \( f + g \)?**
**Options:**
- **A.** The domain of \( f + g \) is \( \} \).
*(This seems to be a typographical error and is not a valid interval.)*
- **B.** The domain of \( f + g \) is \( (-\infty, \infty) \).
*(Correct)*
- **C.** The domain of \( f + g \) is \( \varnothing \).
*(Incorrect, as \( f + g \) is defined for all real numbers.)*
**Correct Choice:**
**B. The domain of \( f + g \) is \( (-\infty, \infty) \).**
### 7. **Simplifying \( f - g \):**
\[
f - g = -2x^2 - 4x + 38
\]
**This is already in its simplest form.**
---
**Summary of Results:**
- \( f + g = 4x - 26 \) with domain \( (-\infty, \infty) \)
- \( f - g = -2x^2 - 4x + 38 \) with domain \( (-\infty, \infty) \)
- \( f \cdot g = -x^4 - 4x^3 + 38x^2 + 24x - 192 \) with domain \( (-\infty, \infty) \)
- \( \frac{f}{g} = \frac{6 - x^2}{(x - 4)(x + 8)} \) with domain \( \mathbb{R} \setminus \{ -8, 4 \} \)
- **The correct domain for \( f + g \) is \( (-\infty, \infty) \).**
Revisado y aprobado por el equipo de tutoría de UpStudy
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