Polynomial functions of degree 2 or more are smooth, continuous functions. See
[link] .
To find the zeros of a polynomial function, if it can be factored, factor the function and set each factor equal to zero. See
[link],[link], and
[link] .
Another way to find the
intercepts of a polynomial function is to graph the function and identify the points at which the graph crosses the
axis. See
[link].
The multiplicity of a zero determines how the graph behaves at the
intercepts. See
[link].
The graph of a polynomial will cross the horizontal axis at a zero with odd multiplicity.
The graph of a polynomial will touch the horizontal axis at a zero with even multiplicity.
The end behavior of a polynomial function depends on the leading term.
The graph of a polynomial function changes direction at its turning points.
A polynomial function of degree
has at most
turning points. See
[link].
To graph polynomial functions, find the zeros and their multiplicities, determine the end behavior, and ensure that the final graph has at most
turning points. See
[link] and
[link].
Graphing a polynomial function helps to estimate local and global extremas. See
[link].
The Intermediate Value Theorem tells us that if
have opposite signs, then there exists at least one value
between
and
for which
See
[link].
Section exercises
Verbal
What is the difference between an
intercept and a zero of a polynomial function
The
intercept is where the graph of the function crosses the
axis, and the zero of the function is the input value for which
If a polynomial function of degree
has
distinct zeros, what do you know about the graph of the function?
Explain how the Intermediate Value Theorem can assist us in finding a zero of a function.
If we evaluate the function at
and at
and the sign of the function value changes, then we know a zero exists between
and
Explain how the factored form of the polynomial helps us in graphing it.
If the graph of a polynomial just touches the
axis and then changes direction, what can we conclude about the factored form of the polynomial?
There will be a factor raised to an even power.
Algebraic
For the following exercises, find the
or
t -intercepts of the polynomial functions.