polynomial functions algebra iii, sec. 2.2 objective use transformations to sketch graphs. use the...
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Polynomial Functions Algebra III, Sec. 2.2
Objective
Use transformations to sketch graphs. Use the Leading Coefficient Test to determine the end behaviors of graphs.Find and use the real zeros. Use the Intermediate Value Theorem to help locate the real zeros.
Important Vocabulary
Continuous – the graph has no breaks, holes, or gaps
Repeated Zero – the zeros from recurring factors
Test Intervals – intervals used to choose x-values to determine the value of the polynomial fn
Intermediate Value Theorem – given two endpoints [a, b] of a continuous fn, there is at least one y value for every x between a and b
Graphs of Polynomial FnsName two basic features of the graphs of polynomial functions.
1. Continuous
2. Only smooth, rounded turns
Example (on your handout)
Will the graph of look more like the
graph of or the graph of ?
Odd degree similar to x3
Example 1Sketch the graph of each function.
a)
Even degree similar to x2
Vertical shrink
Shift right 8
Example 1Sketch the graph of each function.
b)
Even degree similar to x2
Shift down 5
The Leading Coefficient TestFor odd degree polynomials,
If the LC is positive ______________________________
If the LC is negative ______________________________
For even degree polynomials,
If the LC is positive ______________________________
If the LC is negative ______________________________
Example 2Describe the right-hand and left-hand behavior of the graph of each function.
a)
Even degree
Negative LC
So the graph falls to the left and to the right
Example 2Describe the right-hand and left-hand behavior of the graph of each function.
b)
Odd degree
Positive LC
So the graph falls to the left and rises to the right
Example (on your handout)
Describe the right-hand and left-hand behavior of the graph of each function.
Zeros of Polynomial Fns
On the graph of a polynomial function,
turning points are
________________________________________________
________________________________________________
________________________________________________
the relative minima or relative maxima…
points at which the graph changes between increasing and decreasing…
Zeros of Polynomial Fns
Let f be a polynomial function of degree n.
The graph of f has, at most, __________ turning
points.
The function f has , at most, __________ real zeros.
n
n – 1
Zeros of Polynomial Fns
Let f be a polynomial function and let a be a real number. Four equivalent statements about the real zeros of f.
1.
2.
3.
4.
x = a is a zero of the function f
x = a is a solution of the polynomial equation
(x – a) is a factor of the polynomial f(x)
(a, 0) is an x-intercept of the graph of f
Example 3
Find all the real zeros of f(x). Then determine the number of turning points of the graph of the function.
If a polynomial function f has a repeated zero
x = 3 with multiplicity 4, the graph of f
___________ the x-axis at x = 3.
If a polynomial function f has a repeated zero
x = 4 with multiplicity 3, the graph of f
___________ the x-axis at x = 4.
touches
crosses
Example 4Sketch the graph of
Example (on your handout)
Sketch the graph of
Intermediate Value Theorem
If (a, f(a)) and (b, f(b)) are two points on the graph of a polynomial function, then for any number d between f(a) and f(b) there must be a number c between a and b such that f(c)=d.
Intermediate Value Theorem
The Intermediate Value Theorem helps you locate the real zeros of a polynomial function.
If you can find a value x=a at which a polynomial function is positive, and another value x=b at which it is negative, you can conclude that the function has at least one real zero between these two values.
Example 6Use the Intermediate Value Theorem to approximate the real zero(s) of the function.
First, create a table of function values. x -x5+3x3-2x+2 f(x)
-2
-1
0
1
2
sign change a real zero
must be
between 1 &
2
x -x5+3x3-2x+2 f(x)
-2 -(-2)5+3(-2)3-2(-2)+2
-1
0
1
2
x -x5+3x3-2x+2 f(x)
-2 -(-2)5+3(-2)3-2(-2)+2 14
-1
0
1
2
x -x5+3x3-2x+2 f(x)
-2 -(-2)5+3(-2)3-2(-2)+2 14
-1 -(-1)5+3(-1)3-2(-1)+2
0
1
2
x -x5+3x3-2x+2 f(x)
-2 -(-2)5+3(-2)3-2(-2)+2 14
-1 -(-1)5+3(-1)3-2(-1)+2 2
0
1
2
x -x5+3x3-2x+2 f(x)
-2 -(-2)5+3(-2)3-2(-2)+2 14
-1 -(-1)5+3(-1)3-2(-1)+2 2
0 -(0)5+3(0)3-2(0)+2
1
2
x -x5+3x3-2x+2 f(x)
-2 -(-2)5+3(-2)3-2(-2)+2 14
-1 -(-1)5+3(-1)3-2(-1)+2 2
0 -(0)5+3(0)3-2(0)+2 2
1
2
x -x5+3x3-2x+2 f(x)
-2 -(-2)5+3(-2)3-2(-2)+2 14
-1 -(-1)5+3(-1)3-2(-1)+2 2
0 -(0)5+3(0)3-2(0)+2 2
1 -(1)5+3(1)3-2(1)+2
2
x -x5+3x3-2x+2 f(x)
-2 -(-2)5+3(-2)3-2(-2)+2 14
-1 -(-1)5+3(-1)3-2(-1)+2 2
0 -(0)5+3(0)3-2(0)+2 2
1 -(1)5+3(1)3-2(1)+2 2
2
x -x5+3x3-2x+2 f(x)
-2 -(-2)5+3(-2)3-2(-2)+2 14
-1 -(-1)5+3(-1)3-2(-1)+2 2
0 -(0)5+3(0)3-2(0)+2 2
1 -(1)5+3(1)3-2(1)+2 2
2 -(2)5+3(2)3-2(2)+2
x -x5+3x3-2x+2 f(x)
-2 -(-2)5+3(-2)3-2(-2)+2 14
-1 -(-1)5+3(-1)3-2(-1)+2 2
0 -(0)5+3(0)3-2(0)+2 2
1 -(1)5+3(1)3-2(1)+2 2
2 -(2)5+3(2)3-2(2)+2 -10
Example 6Use the Intermediate Value Theorem to approximate the real zero(s) of the function.
Now, divide the interval into tenths & evaluate…
Example 6Use the Intermediate Value Theorem to approximate the real zero(s) of the function.
You can also evaluate the graph…
