Question

What are the possible number of positive, negative, and complex zeros of f(x) = 3x^4 - 5x^3 - x^2 - 8x + 4 ?

Answer 1

Well, if they just want the number of roots, then it will be a total of 4 , 2 complex, 2 reals

Answer 2

My teacher wants the possible number of positive real, negative real, and complex. Knowing that there are 2 complex zeroes narrows down the answer.

Answer 3

Is the number of positive real 3 or 1 and the negative 1, or is it vice versa?

Answer 4

Then apply Descartes' Rule, have you learn that before?

Answer 5

I have to go now, there's a tutorial on that here: http://www.purplemath.com/modules/drofsign.htm

Try it out :)

Answer 6

Ok

Answer 7

Got it! Thanks!