How many sign changes are in the polynomial f(x) = 3x^3 + 7x^2 + 9x + 1
A. 0
B. 1
C. 2
D. 3

@hartnn

Question

How many sign changes are in the polynomial f(x) = 3x^3 + 7x^2 + 9x + 1
	A.	0
	B.	1
	C.	2
	D.	3

@hartnn

dumbsearch2 · Answer

May you help me?

I know it has something to do with the roots, but I really don't understand the sign change thingy.

dumbsearch2 · Answer

hartnn · Answer

hartnn · Answer

lol yes

dumbsearch2 · Answer

Could you help guide me through it?

And lol, we posted it at the *exactly* same time! :D

anonymous · Answer

all the coefficients are positive, which is why this might be confusing

anonymous · Answer

so it is kind of a bad example to work out the changes in sign for the first time
$$f(x)=3x^3-4x^2+2x+1$$ has 3 changes in sign

anonymous · Answer

from 3 to -4 and from -4 to 2
oh actually it only as two changes

dumbsearch2 · Answer

So how would I apply this to my problem? @satellite73

dumbsearch2 · Answer

How many changes does it have?