Use Descartes' rule of signs to describe the roots of the polynomial:
f(x)=3x^5-4x^3+3x^2+2x-1

Question

Use Descartes' rule of signs to describe the roots of the polynomial: 
f(x)=3x^5-4x^3+3x^2+2x-1

dtan5457 · Answer

Choices? Or no multiple choice?

ria23 · Answer

No, I have to supply the answer, I kind of remember how to do it... But I'm a little fuzzy.

dtan5457 · Answer

For the positive roots.

3x^5-4x^3+3x^2+2x-1

Find how many sign changes

goes from a negative to a positive, back to a negative. so 2 or 0 root change

dtan5457 · Answer

For the negative roots.

make every x negative.

3(-x^5)-4(-x^3)+3(-x)^2+2(-x)-1

If you simplify that out

you should get -3x^5+4x^3+3x^2-2x-1

again, 2 or 0 roots

ria23 · Answer

So...$$\le2$$?
For both?

dtan5457 · Answer

No, a root can't be 1 so it has to be 2 or 0

dtan5457 · Answer

for both

ria23 · Answer

Ok. c:
Thank yhu n.n