Lec 38  Graphs of Polynomials: Multiplicities  Summary and Q&A
TL;DR
Learn how to identify the zeros of polynomial functions by analyzing their graphs and understand the behavior of the graph based on the multiplicities of the zeros.
Key Insights
 🔍 Graphing a polynomial function:
 The knowledge of xintercepts helps in understanding the shape of the polynomial graph and whether it goes up or down.
 To find the xintercepts of a polynomial, one can plot a table of values and identify the points where the function equals zero.
 Long division can be used to factorize the given polynomial and find all the xintercepts.
 A cubic polynomial can have at most three roots.
 Plotting the function along with the table of values helps visualize the curve of the polynomial.
 Understanding the behavior of the graph around the xintercepts is crucial and related to the multiplicities of the factors.
 Polynomial factors with odd multiplicities will result in graphs crossing the xaxis, while those with even multiplicities will bounce off.
 The shape of the graph changes with the degree of the polynomial, with evendegree polynomials appearing flatter near the xaxis and odddegree polynomials being steeper.
 Identifying the multiplicities of the zeros allows for a better understanding of the graph and the polynomial function.
Transcript
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Questions & Answers
Q: How can we identify the xintercepts of a polynomial function using its graph?
To find the xintercepts, we can plot the function values at certain points and observe where the function crosses the xaxis. By doing this, we can determine the xvalues that correspond to the zeros of the polynomial.
Q: What is the significance of the multiplicities of the zeros in a polynomial function?
The multiplicities of the zeros indicate how many times each zero is repeated in the factored form of the polynomial. This information helps us understand the behavior of the graph near the zeros. Odd multiplicities result in the graph crossing the xaxis, while even multiplicities cause the graph to bounce off the xaxis.
Q: How does the graph of a polynomial function behave near its zeros?
If a zero has an odd multiplicity, the graph of the polynomial will cross the xaxis at that point. On the other hand, if a zero has an even multiplicity, the graph will bounce off the xaxis at that point.
Q: How can we determine the factored form of a polynomial function from its graph?
By identifying the xintercepts (zeros) of the function using its graph, we can use the knowledge of these zeros to write the polynomial in factored form. This involves applying long division to the polynomial and factoring out the corresponding factors for each zero.
Summary & Key Takeaways

By analyzing the graph of a polynomial function, we can identify its zeros and determine whether it is in factored form or nonfactored form.

To find the xintercepts (zeros) of a polynomial function, one method is to plot the function values at certain points and observe where the function crosses the xaxis.

The behavior of the graph near the zeros can be determined by looking at the factors of the polynomial and their multiplicities. Odddegree factors result in the graph crossing the xaxis, while evendegree factors lead to the graph bouncing off the xaxis.