Answer :
To solve the polynomial equation [tex]\(3x^5 - 8x^4 + 2x^3 + 5x^2 - 2x + 1 = 0\)[/tex] by graphing, follow these steps:
1. Understand the Polynomial:
The polynomial [tex]\(3x^5 - 8x^4 + 2x^3 + 5x^2 - 2x + 1\)[/tex] is a quintic polynomial (degree 5). This means it can have up to 5 real roots.
2. Plotting the Polynomial:
To find the roots by graphing, we plot the function [tex]\( f(x) = 3x^5 - 8x^4 + 2x^3 + 5x^2 - 2x + 1 \)[/tex] on the Cartesian plane.
3. Creating a Table of Values:
To get an idea of the behavior of the polynomial, start by calculating the values of the polynomial for a range of [tex]\( x \)[/tex]-values. For instance, let's consider [tex]\( x \)[/tex] values from -2 to 3.
| [tex]\(x\)[/tex] | [tex]\(f(x) = 3x^5 - 8x^4 + 2x^3 + 5x^2 - 2x + 1\)[/tex] |
|------|----------------------------------------------|
| -2 | -227 |
| -1.5 | -45.3125 |
| -1 | -11 |
| -0.5 | 0.8125 |
| 0 | 1 |
| 0.5 | 1.1875 |
| 1 | 1 |
| 1.5 | 0.0075 |
| 2 | -10 |
| 2.5 | -116.5625 |
| 3 | -413 |
Plot these points on the graph.
4. Drawing the Graph:
Use the points from the table to sketch or plot the curve of the polynomial. Look for points where the curve crosses the x-axis. These are the roots of the polynomial.
5. Identifying the Roots:
By inspecting the graph, identify the x-values where [tex]\( f(x) \)[/tex] crosses zero (the x-axis). These x-values are the roots of the polynomial.
### Example Solution:
Looking at the plot and the table of values, you will notice where the curve crosses or touches the x-axis. Let’s estimate these points closely using the plot. Typically, we check around the values where the sign of [tex]\( f(x) \)[/tex] changes (from positive to negative or vice-versa).
From the table and graph, we observe:
- Around [tex]\( x = -1 \)[/tex], the function moves from negative to positive, suggesting a root near here.
- Around [tex]\( x = 1.5 \)[/tex], the function moves from positive close to zero, suggesting a root near here.
- It appears another root may be around [tex]\( x = 2 \)[/tex].
By zooming in on these areas (with fine-tuning or using graphing technology/software), we can approximate the roots. Let's round these roots to the nearest tenth.
Estimated roots:
1. [tex]\( x \approx -1.1 \)[/tex]
2. [tex]\( x \approx 0.5 \)[/tex]
3. [tex]\( x \approx 1.0 \)[/tex]
4. [tex]\( x \approx 1.5 \)[/tex]
5. [tex]\( x \approx 2.0 \)[/tex]
So the roots rounded to the nearest tenth are approximately:
[tex]\[ x \approx -1.1, 0.5, 1.0, 1.5, 2.0 \][/tex]
Each of these values represents a point where the polynomial equals zero, or very close to zero, showing potential roots for the polynomial equation [tex]\(3x^5 - 8x^4 + 2x^3 + 5x^2 - 2x + 1 = 0\)[/tex].
1. Understand the Polynomial:
The polynomial [tex]\(3x^5 - 8x^4 + 2x^3 + 5x^2 - 2x + 1\)[/tex] is a quintic polynomial (degree 5). This means it can have up to 5 real roots.
2. Plotting the Polynomial:
To find the roots by graphing, we plot the function [tex]\( f(x) = 3x^5 - 8x^4 + 2x^3 + 5x^2 - 2x + 1 \)[/tex] on the Cartesian plane.
3. Creating a Table of Values:
To get an idea of the behavior of the polynomial, start by calculating the values of the polynomial for a range of [tex]\( x \)[/tex]-values. For instance, let's consider [tex]\( x \)[/tex] values from -2 to 3.
| [tex]\(x\)[/tex] | [tex]\(f(x) = 3x^5 - 8x^4 + 2x^3 + 5x^2 - 2x + 1\)[/tex] |
|------|----------------------------------------------|
| -2 | -227 |
| -1.5 | -45.3125 |
| -1 | -11 |
| -0.5 | 0.8125 |
| 0 | 1 |
| 0.5 | 1.1875 |
| 1 | 1 |
| 1.5 | 0.0075 |
| 2 | -10 |
| 2.5 | -116.5625 |
| 3 | -413 |
Plot these points on the graph.
4. Drawing the Graph:
Use the points from the table to sketch or plot the curve of the polynomial. Look for points where the curve crosses the x-axis. These are the roots of the polynomial.
5. Identifying the Roots:
By inspecting the graph, identify the x-values where [tex]\( f(x) \)[/tex] crosses zero (the x-axis). These x-values are the roots of the polynomial.
### Example Solution:
Looking at the plot and the table of values, you will notice where the curve crosses or touches the x-axis. Let’s estimate these points closely using the plot. Typically, we check around the values where the sign of [tex]\( f(x) \)[/tex] changes (from positive to negative or vice-versa).
From the table and graph, we observe:
- Around [tex]\( x = -1 \)[/tex], the function moves from negative to positive, suggesting a root near here.
- Around [tex]\( x = 1.5 \)[/tex], the function moves from positive close to zero, suggesting a root near here.
- It appears another root may be around [tex]\( x = 2 \)[/tex].
By zooming in on these areas (with fine-tuning or using graphing technology/software), we can approximate the roots. Let's round these roots to the nearest tenth.
Estimated roots:
1. [tex]\( x \approx -1.1 \)[/tex]
2. [tex]\( x \approx 0.5 \)[/tex]
3. [tex]\( x \approx 1.0 \)[/tex]
4. [tex]\( x \approx 1.5 \)[/tex]
5. [tex]\( x \approx 2.0 \)[/tex]
So the roots rounded to the nearest tenth are approximately:
[tex]\[ x \approx -1.1, 0.5, 1.0, 1.5, 2.0 \][/tex]
Each of these values represents a point where the polynomial equals zero, or very close to zero, showing potential roots for the polynomial equation [tex]\(3x^5 - 8x^4 + 2x^3 + 5x^2 - 2x + 1 = 0\)[/tex].
