Chapter 0: Problem 55
In Exercises \(55-58\), find a good window setting for the graph of the function. The graph should show all the zeros of the polynomial. $$ f(x)=x^{3}-22 x^{2}+17 x+19 $$
Short Answer
Expert verified
Plot the function with initial x-range of -10 to 30, then refine the window settings to make all zeros visible, e.g., x-range of -5 to 25.
Step by step solution
01
- Understand the Function
The function given is a cubic polynomial: ewline f(x) = x^3 - 22x^2 + 17x + 19. ewline The zeros of the function are the values of x where f(x) = 0.
02
- Identify the Degree and Leading Coefficient
The degree of the polynomial is 3, which is the highest power of x, and the leading coefficient is 1 (the coefficient of x^3). This implies that the graph of the function will have one or two turning points.
03
- Determine the Range of x-values
To ensure that all zeros of the polynomial are displayed, consider estimating a reasonable range for the x-values. A good starting point can be to use the fundamental theorem of algebra which suggests there will be 3 roots, real or complex.
04
- Use Graphing Tools
Use a graphing calculator or software to plot the function. Start with a wide window setting, for example, set the x-range from -10 to 30 (based on possible expected zeros) and y-range appropriate to the values of the function within this range.
05
- Refine the Window Setting
After plotting the graph with initial settings, adjust the window settings to zoom in or out until all the zeros are visible. For example, an x-range from -5 to 25 and a suitable y-range may show a clear view of the polynomial's behavior.
06
- Check for All Zeros
Ensure that the graph shows all the points where the function crosses the x-axis. These crossings represent the zeros of the polynomial.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
cubic polynomial
A cubic polynomial is a polynomial of degree three, which means the highest exponent of the variable is three. The general form of a cubic polynomial is \[f(x) = ax^3 + bx^2 + cx + d\]where
- \(a\), \(b\), \(c\), and \(d\) are constants
- \(a ≠0\) (since it's cubic)
finding zeros
Finding the zeros of a polynomial involves solving the equation \(f(x) = 0\). For a cubic polynomial like \(f(x) = x^3 - 22x^2 + 17x + 19\), this means finding the values of \(x\) where the function equals zero. There are several methods to find these zeros:
- Factoring: Sometimes, a polynomial can be factored into simpler components, although this method is often challenging for cubic polynomials.
- Graphing: Plotting the function on a graph to visually identify where it crosses the \(x\)-axis.
- Using a graphing calculator: Graphing tools can provide precise zeroes by using numerical methods.
graphing calculator
A graphing calculator is a useful tool for visualizing polynomials and finding their characteristics such as zeros, intercepts, and turning points.To graph a cubic polynomial like \(f(x) = x^3 - 22x^2 + 17x + 19\), follow these steps:
- Input the function: Enter the polynomial into the calculator.
- Set the window: Choose a suitable \(x\)-range and \(y\)-range. Start with a broad range, e.g., \(-10\ to \30\) for \(x\) and an appropriate range for \(y\).
- Plot the graph: Assess the preliminary graph to see the general shape and where it crosses the \(x\)-axis.
- Refine the window: Adjust the window settings to zoom in on areas where the function crosses the \(x\)-axis to precisely find all zeros.
- Check the zeros: Use the calculator's function to find zeros accurately.