3 1 Polynomial Functions and their Graphs fx

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3. 1 Polynomial Functions and their Graphs

3. 1 Polynomial Functions and their Graphs

f(x) = 5 3 x + 4 6 x – 3 2 x +

f(x) = 5 3 x + 4 6 x – 3 2 x + 7 x - 6

 • The graph of a polynomial function is always a smooth curve –

• The graph of a polynomial function is always a smooth curve – no breaks, holes, or corners. • Recall section 2. 4 about stretches, shifts, etc. • EX: Graph y = x 4 and y = (x – 2)4

Polynomial?

Polynomial?

End Behavior & the Leading Coefficient • Tells what happens as x becomes large

End Behavior & the Leading Coefficient • Tells what happens as x becomes large in the positive or negative direction. x gets bigger x gets smaller

End behavior is determined by the term that contains the highest power of x.

End behavior is determined by the term that contains the highest power of x. (leading coefficient) Always opposite Always the same

EX Determine the end behavior: • f(x) = -3 x 3 + 20 x

EX Determine the end behavior: • f(x) = -3 x 3 + 20 x 2 + 60 x + 2 • f(x) = -7 x 4 + 5 x 3 + 4 x - 7

Using Zeros to Graph If P is a polynomial and c is a real

Using Zeros to Graph If P is a polynomial and c is a real number, then the following are equivalent: • ‘c’ is a zero if P(c) = 0 • X = c is an x-intercept of the graph of P • X = c is a solution of the equation P(x) = 0 • X – c is a factor of P(x) Find factors Find zeros

Find the zeros by factoring: • P(x) = x 2 + x - 6

Find the zeros by factoring: • P(x) = x 2 + x - 6

If you have positive and negative yvalues, your polynomial has to have at least

If you have positive and negative yvalues, your polynomial has to have at least one zero.

Table must include: • Zeros • A point in between each zero • Y-intercept

Table must include: • Zeros • A point in between each zero • Y-intercept Need to know end behavior

P(x) = (x + 2)(x – 1)(x – 3) • Find the zeros and

P(x) = (x + 2)(x – 1)(x – 3) • Find the zeros and graph. X F(x) -2 0 1 0 3 0

Multiplicity m is the exponent Passes through Bounces off

Multiplicity m is the exponent Passes through Bounces off

P(x) = (x + 2)(x – 1)(x – 3)2 • Find the zeros and

P(x) = (x + 2)(x – 1)(x – 3)2 • Find the zeros and graph. X F(x) -2 0 1 0 3 0

PHONE NUMBER • Key in the 1 st three digits of your phone number

PHONE NUMBER • Key in the 1 st three digits of your phone number (not the area code) • Multiply by 80 • Add 1 • Multiply by 250 • Add the last four digits of your phone # AGAIN • Subtract 250 • Divide by 2 • SEE YOUR PHONE NUMBER ON YOUR CALCULATOR? ? ?

P(x) = 3 x 4 – 5 x 3 – 12 x 2 •

P(x) = 3 x 4 – 5 x 3 – 12 x 2 • Find the zeros, y-int, and graph. X F(x) -4/3 0 0 0 3 0

P(x) = x 3 + 3 x 2 – 9 x - 27 •

P(x) = x 3 + 3 x 2 – 9 x - 27 • Find the zeros, y-int, and graph. X F(x) -3 0

Local Extrema The number of local extrema must be less than the degree.

Local Extrema The number of local extrema must be less than the degree.

P(x) = 3 x 4 – 5 x 3 – 12 x 2 •

P(x) = 3 x 4 – 5 x 3 – 12 x 2 • Find the zeros, y-int, and graph. X F(x) -4/3 0 0 0 3 0

P(x) = (x + 2)(x – 1)(x – 3) • Find the zeros and

P(x) = (x + 2)(x – 1)(x – 3) • Find the zeros and graph. X F(x) -2 0 1 0 3 0

Homework pg 262 #1, 3, 5 - 10, 13, 15, 16, 21, 25 -45

Homework pg 262 #1, 3, 5 - 10, 13, 15, 16, 21, 25 -45 odd