140 likes | 331 Views
7.5 and 7.6 Roots and Zeros of a Function. Zeros, Factors & Roots Summary:. c is a zero of f(x) x - c is a factor of f(x) c is a root/solution of f(x) = 0 If c is real, (c,0) is an x- intercept. Fundamental Theorem of Algebra.
E N D
7.5 and 7.6 Roots and Zeros of a Function
Zeros, Factors & RootsSummary: • c is a zero of f(x) • x - c is a factor of f(x) • c is a root/solution of f(x) = 0 • If c is real, (c,0) is an x-intercept.
Fundamental Theorem of Algebra Every polynomial equation with degree greater than zero has at least one root in the set of complex #’s. An nth degree polynomial equation of the form P(x) = 0 • has exactly n roots in the set of complex #’s. • has exactly n zeros.
Rational Zero Theorem • can help us limit the # of possible zeros to test • p is a factor of the constant • q is a factor of the leading coefficient
Ex 1List all the possible rational roots. • f(x) = x4 + 7x3 – 15 • g(x) = 6x3 + 6x2 – 15x - 2
EX 2Find all the zeros. • f(x) = x4 + x3 - 19x2 + 11x + 30
Complex Conjugates Theorem if a + bi is a zero, then a - bi is a zero Irrational Root Theorem
EX 3Find all the zeros. • f(x) = x3– 4x2 + 6x – 4
EX 4Find all the zeros. • f(x) = 3x3 - 5x2 - 14x - 4
EX 5Find all the zeros. • f(x) = 6x4– 5x3 - 38x2 - 5x + 6
EX 6Find all the zeros. • f(x) = 6x4– 17x3 + 8x2 + 8x - 3
Ex 7Write the polynomial function of least degree w/integer coefficients whose zeros include the following: Example 5-1c
Ex 8Write the polynomial function of least degree w/integer coefficients whose zeros include the following: Example 5-1c