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Warm-Up: November 27, 2012. Solve x 3 +2x 2 -2x-1=0. Homework Questions?. Zeros of Polynomial Functions. Section 7.5. Essential Question. How can we find every zero of a polynomial function?. Improved Guess and Check. There are a limited number of possible rational roots of a polynomial.
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Warm-Up: November 27, 2012 • Solve x3+2x2-2x-1=0
Zeros of Polynomial Functions Section 7.5
Essential Question • How can we find every zero of a polynomial function?
Improved Guess and Check • There are a limited number of possible rational roots of a polynomial. • Write down all the factors of the constant term. • Write down all the factors of the leading coefficient. • Any rational root must be of the form • This is called the Rational Root Theorem.
Example 1 • Find all roots of
You-Try #1 • Find all roots of
Reminder • All of the following mean basically the same thing: • Root • Zero • X-intercept • Solutions • They all mean “solve for x”
Extra Step for Finding Zeros • First replace f(x) with 0 • Then solve for x
Example 2 • Find all the zeros of
You-Try #2 • Find all the zeros of
Assignment • Page 464 #11-25 odd • Bring your graphing calculator to class every day (especially tomorrow)
Warm-Up: November 28, 2012 • Simplify each of the following
Reminder • All of the following mean basically the same thing: • Root • Zero • X-intercept • Solutions • They all mean “solve for x”
Extra Step for Finding Zeros • First replace f(x) with 0 • Then solve for x
Example 3 • Find all the zeros of
Warm-Up: November 29, 2012 • Use the quadratic formula to find the zeros of
You-Try #3 • Find all the zeros of
Multiplicity • If (x-r) is a factor that occurs m times in the factorization of a polynomial, then r is a root with multiplicitym. • If m is even, the graph will touch but not cross the x-axis at r. • If m is odd, the graph will cross the x-axis at r.
Example 5 • Write a polynomial function, P, in factored form and in standard form by using the given information:
You-Try #5 • Write a polynomial function, P, in factored form and in standard form by using the given information:
Warm-Up: November 30, 2012 • Find all zeros of
Complex Conjugate Root Theorem • If is a root/zero, then must also be a root/zero.
Example 6 • Write a polynomial function, P, in factored form and in standard form by using the given information:
You-Try #6 • Write a polynomial function, P, in factored form and in standard form by using the given information:
Assignment • Page 464 #27-33 odd, 41-49 odd