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**Part 11a: Modulus Functions**
1. **i) \( f(x) = |-3x + 1| + 1**
- **Domain:** All real numbers
- **Range:** \( [1, \infty) \)
2. **ii) \( f(x) = |x^2 + 5x + 4| - 2**
- **Domain:** All real numbers
- **Range:** \( [-2, \infty) \)
3. **iii) \( f(x) = |x^2 + x - 6| - 3**
- **Domain:** All real numbers
- **Range:** \( [-3, \infty) \)
**Part 11b: Quadratic Function Analysis**
1. **i) Intercepts**
- **Y-intercept:** \( (0, -2) \)
- **X-intercepts:** \( \left(\frac{2}{3}, 0\right) \) and \( \left(-\frac{1}{2}, 0\right) \)
2. **ii) Maximum Point:**
- Vertex at \( \left(\frac{1}{12}, -\frac{47}{24}\right) \)
3. **iii) Graphs of \( f(x) = -6x^2 + x - 2 \) and \( g(x) = |6x^2 + x - 2| \)**
- Plot the quadratic function and its absolute value to visualize the behavior of both functions.
Solución
Let's break down the problem step by step.
### Part 11a: Sketching Modulus Functions
#### i) \( f(x) = |-3x + 1| + 1 \)
1. **Domain**: The domain of \( f(x) \) is all real numbers, \( (-\infty, \infty) \).
2. **Range**: Since the absolute value function is always non-negative, the minimum value of \( f(x) \) occurs when \( |-3x + 1| = 0 \). This happens when \( -3x + 1 = 0 \) or \( x = \frac{1}{3} \). Thus, the minimum value of \( f(x) \) is \( 1 \). Therefore, the range is \( [1, \infty) \).
#### ii) \( f(x) = |x^2 + 5x + 4| - 2 \)
1. **Domain**: The domain is all real numbers, \( (-\infty, \infty) \).
2. **Finding the roots of the quadratic**:
\[
x^2 + 5x + 4 = 0
\]
Using the quadratic formula:
\[
x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} = \frac{-5 \pm \sqrt{25 - 16}}{2} = \frac{-5 \pm 3}{2}
\]
This gives us roots \( x = -1 \) and \( x = -4 \).
3. **Range**: The minimum value of \( |x^2 + 5x + 4| \) occurs at the vertex of the parabola, which is at \( x = -\frac{b}{2a} = -\frac{5}{2} = -2.5 \). Evaluating \( f(-2.5) \):
\[
f(-2.5) = |(-2.5)^2 + 5(-2.5) + 4| - 2 = |6.25 - 12.5 + 4| - 2 = |-2.25| - 2 = 2.25 - 2 = 0.25
\]
Therefore, the range is \( [-2, \infty) \).
#### iii) \( f(x) = |x^2 + x - 6| - 3 \)
1. **Domain**: The domain is all real numbers, \( (-\infty, \infty) \).
2. **Finding the roots of the quadratic**:
\[
x^2 + x - 6 = 0
\]
Using the quadratic formula:
\[
x = \frac{-1 \pm \sqrt{1 + 24}}{2} = \frac{-1 \pm 5}{2}
\]
This gives us roots \( x = 2 \) and \( x = -3 \).
3. **Range**: The vertex occurs at \( x = -\frac{b}{2a} = -\frac{1}{2} \). Evaluating \( f(-0.5) \):
\[
f(-0.5) = |(-0.5)^2 + (-0.5) - 6| - 3 = |0.25 - 0.5 - 6| - 3 = |-6.25| - 3 = 6.25 - 3 = 3.25
\]
Therefore, the range is \( [-3, \infty) \).
### Part 11b: Quadratic Function Analysis
Given the function \( f(x) = -6x^2 + x - 2 \):
#### i) Finding the intercepts
1. **Y-intercept**: Set \( x = 0 \):
\[
f(0) = -6(0)^2 + (0) - 2 = -2
\]
So, the y-intercept is \( (0, -2) \).
2. **X-intercepts**: Set \( f(x) = 0 \):
\[
-6x^2 + x - 2 = 0
\]
Using the quadratic formula:
\[
x = \frac{-1 \pm \sqrt{1 + 48}}{-12} = \frac{-1 \pm 7}{-12}
\]
This gives us:
\[
x = \frac{-8}{-12} = \frac{2}{3}, \quad x = \frac{6}{-12} = -\frac{1}{2}
\]
So, the x-intercepts are \( \left(\frac{2}{3}, 0\right) \) and \( \left(-\frac{1}{2}, 0\right) \).
#### ii) Maximum or Minimum Point
The vertex occurs at \( x = -\frac{b}{2a} = -\frac{1}{-12} = \frac{1}{12} \). Evaluating \( f\left(\frac{1}{12}\right) \):
\[
f\left(\frac{1}{12}\right) = -6\left(\frac{1}{12}\right)^2 + \left(\frac{1}{12}\right) - 2 = -\frac{6}{144} + \frac{1}{12} - 2 = -\frac{1}{24} + \frac{2}{24} - \frac{48}{24} = -\frac{47}{24}
\]
Thus, the maximum point is \( \left(\frac{1}{12}, -\frac{47}{24}\right) \).
#### iii) Sketching the Graphs
To sketch the graphs of \( f(x) = -6x^2 + x - 2 \) and \( g(x) = |6x^2 + x - 2| \), we can plot the quadratic function and its absolute value.
Now, I will proceed to calculate the necessary values for the graphs of \( f(x) \) and \( g(x) \).
### Calculating the Graphs
Let's calculate the vertex and intercepts for \( g(x) = |6x^2 + x - 2| \) to understand its shape.
1. **Finding the roots of \( 6x^2 + x - 2 = 0 \)**:
\[
x = \frac{-1 \pm \sqrt{1 + 48}}{12} = \frac{-1 \pm 7}{12}
\]
This gives us roots \( x = \frac{1}{3} \) and \( x = -\frac{2}{3} \).
2. **Finding the vertex of \( 6x^2 + x - 2 \)**
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