Question

Can someone help me with a worksheet on Fundamental Theorem of Algebra and Descaretes rule of signs

Answer 1

got a question?

Answer 2

Its the same as yesterday just a different function.

Answer 3

my memory is not that good
you got a specific function ?`

Answer 4

Use the Fundamental Theorem of Algebra to determine the total number of zeros of f(x)=x^4-x^3+7x^2-9x-18

Answer 5

it is a polynomial of degree 4
there are 4 zeros although some might be complex and some might be repeated
do you need to find possible number of positive and negative zeros, or do you just need to find the actual zeros?

Answer 6

i need help on a whole worksheet on this I know most of it just a few questions i need help with

Answer 7

i got ten minutes and can help if you post a screenshot

Answer 8

i have 1-3c done and i know how to do 4a and b

Answer 9

@satellite73

Answer 10

lets go to descartes rule of sign
check the changes in sign of the coefficient of \(x^4-x^3+7x^2-9x-18\)

Answer 11

there are 3 from \(1\) to \(-1\)
from \(-1\) to \(7\) and from \(7\) to \(-9\_

Answer 12

that means there are either 3 positive zeros ,or one positive zero (you count down by twos)

Answer 13

now given
\[f(x)=x^4-x^3+7x^2-9x-18\] compute
\[f(-x)=x^4+x^3+7x^2+9x-18\] and here there is only one change in sign from \(+9\) to \(-18\)
that means there is a negative zeros

Answer 14

gotta run, good luck

Answer 15

So there would be 3?

Answer 16

Alright thank you soo much for helping