2 Flashcards
complex number
any number that can be written in the form a + bi
where a and b are real numbers
ex: 2 + 3i
conjugate zero theorem
if P(x) a polynomial function with only real coefficients, has a + bi as a zero, then its conjugate is also a real zero
root -k
i root k
where k is greater than zero
P(x) zeros
if P(x) of degree n, has n zeros, then P(x) = a(x-k1)(x-k2)…(x-kn)
multiplicity
the amount of times a zero occurs in a function
Fundamental Theorem of Algebra
Every polynomial of degree 1 or more has at least one complex zero
number of zeros theorem
polynomial of degree n has at most n distinct complex zeros
larger multiplicities…?
stretch out the graph
rational zeros theorem
let p(x) = classical form
if p/q is a zero of p(x), then p is a factor of a0 and q is a factor of an
multiplicity one
graph crosses the x axis
even multiplicity
graph bounces/turns at x axis
odd multiplicity >1
graph crosses, and is tangent, at x axis
boundness theorem (a)
If c > 0 and all numbers in the bottom row of the synthetic division are positive, then P(x) has no zero greater than c. The number c is called an upper bound.
*dividend has positive leading coefficient, real coefficients, and divided by x-c
boundness theorem (b)
If c < 0 and the numbers in the bottom row of the synthetic division alternate in sign (with 0 considered positive or negative, as needed), then P(x) has no zero less than c. The number c is called a lower bound.
*dividend has positive leading coefficient, real coefficients, and divided by x-c